OT - Voltage Drop In Trailer Wiring

[DerbyDad03]

I'm reading a voltage drop in my trailer wiring and wondering if it's
normal.

Here's what I've found:

Flat four plug from vehicle reads 12.5V from ground pin to tail light pin
without the trailer plugged in.

Flat four plug from vehicle drops to 10.5V from ground pin to tail light
pin when the trailer is plugged in.

Light fixtures on trailer read 9.5V from when testing both "socket ground
to socket hot" and "ground-screw-into-frame at rear of trailer to socket
hot".

Resistance between trailer's flat four ground wire attached to trailer
tongue and the ground at the sockets and the ground-screw-into-frame at
rear of trailer reads about 2.5 ohms.

The side marker lights have no ground wire, using the self tapping screws
that hold the markers to the trailer shell as the ground. The rear lights
use a ground wire, with the ground provided by a pigtail to a self tapping
screw into the trailer frame.

What would cause a 2 volt drop right at the plug when the trailer is
plugged in and then another 1 volt drop at the fixtures?

Thanks!

[Ralph Mowery]

I would start by giving the plug a good cleaning. Without a load except for
the meter, there will not be any noticable voltage drop at all. In a 12
volt system, it only takes a small ammount of resistance to have a large
voltage drop.

If the lights only pull 1 amp and you have only 1 ohm of resistance, you
will loose 1 volt. You mention 2.5 ohms, If you zeroed out all the
resistance of the meter, that is where you are loosing most of the voltage.
Going back to that 1 amp load, (which is probably not as much as you have)
that 2.5 ohms will drop 2.5 volts under the load of the lights.

I would make sure that the wires going from the battery or switch to the
plug are good and tight with no corrosion on them. Then clean both plug and
socket and make sure the ground wires are tight and don't have any corrosion
under them.

The wires should be put on with lugs, but if the wire is just wrapped around
the screws, that would be a good place to start.

"DerbyDad03" <teama...@eznet.net> wrote in message
news:1868971480398361462.997...@nntp.aioe.org...

[bob haller]

I had all sorts of troubles with a friends trailer used for ministeries........

I finally traced all the troubles to a poor ground on the tow vehicle....

[tra...@optonline.net]

On Friday, August 16, 2013 4:04:16 PM UTC-4, Ralph Mowery wrote:
> I would start by giving the plug a good cleaning. Without a load except for
>
> the meter, there will not be any noticable voltage drop at all. In a 12
>
> volt system, it only takes a small ammount of resistance to have a large
>
> voltage drop.
>
>
>
> If the lights only pull 1 amp and you have only 1 ohm of resistance, you
>
> will loose 1 volt. You mention 2.5 ohms, If you zeroed out all the
>
> resistance of the meter, that is where you are loosing most of the voltage.
>
> Going back to that 1 amp load, (which is probably not as much as you have)
>
> that 2.5 ohms will drop 2.5 volts under the load of the lights.
>
>

That's for sure. IDK how many lights he has, but just 12 watts worth
of lights would be 1 amp, giving him that 2.5 volt drop. On the other
hand, if he has voltage drops without any loads on at all, then
he must have some partial short somewhere.

[Jon Danniken]

On 08/16/2013 11:34 AM, DerbyDad03 wrote:
> I'm reading a voltage drop in my trailer wiring and wondering if it's
> normal.

[snip]

Ralph provided a pretty good answer, so there is no need to repeat what
he already stated.

I will add, however, that I noticed a sizeable drop on my 5-way to 4-way
adaptor, which I ascribed to a typical voltage drop due to
semiconductor(s) (diode and/or transistor) in the adaptor.

The way I dealt with this was to ditch the incandescent bulbs that I
previously had on the trailer for LED units, which have no problem
lighting up nice and bright, despite the lower voltages (the
incandescent bulbs were really dim, and I didn't feel safe driving with
them in such a condition).

Jon

[Tony Hwang]

Hi,
Remeber Ohm's law? Use it.

[Tony Hwang]

Jon Danniken wrote:
> On 08/16/2013 11:34 AM, DerbyDad03 wrote:
>> I'm reading a voltage drop in my trailer wiring and wondering if it's
>> normal.
> [snip]
>
> Ralph provided a pretty good answer, so there is no need to repeat what
> he already stated.
>
> I will add, however, that I noticed a sizeable drop on my 5-way to 4-way
> adaptor, which I ascribed to a typical voltage drop due to
> semiconductor(s) (diode and/or transistor) in the adaptor.
>

Hi,
Typical Si junction voltage drop in semiconductor is ~0.2 Volts.

[DerbyDad03]

Jon Danniken <jonSPAM...@yaSMPAhoo.com> wrote:
> On 08/16/2013 11:34 AM, DerbyDad03 wrote:
>> I'm reading a voltage drop in my trailer wiring and wondering if it's
>> normal.
> [snip]
>
> Ralph provided a pretty good answer, so there is no need to repeat what
> he already stated.
>
> I will add, however, that I noticed a sizeable drop on my 5-way to 4-way
> adaptor, which I ascribed to a typical voltage drop due to
> semiconductor(s) (diode and/or transistor) in the adaptor.

Since I'm running flat four to flat four, there are no electronics involved
in my situation.

>
> The way I dealt with this was to ditch the incandescent bulbs that I
> previously had on the trailer for LED units, which have no problem
> lighting up nice and bright, despite the lower voltages (the
> incandescent bulbs were really dim, and I didn't feel safe driving with
> them in such a condition).
>
> Jon

The LED route is where I'm headed which is why I was checking out the
wiring, just making sure everything was OK. I'm looking at LED replacement
that will plug into my existing bulb socket.

This 1157 replacement bulb says it will run at 7.5 - 14 V

http://www.ledtrailerlights.com/stt/stt_1157.htm

The marker units say they'll run at 9 - 16 V

http://www.ledtrailerlights.com/cm/00-4400.htm

However this complete unit, which plugs into the 1157 socket, doesn't list
a voltage range.

http://www.ledtrailerlights.com/stt/led-insert.htm

I'm guessing the complete unit will be brighter than just the bulb, and I'm
guessing it'll run at the 9.5 V I have at those fixtures, but I'll have to
call the vendor to find out for sure.

I'm assuming that LED's have one brightness. In other words, any voltage
above the minimum produces the maximum brightness, correct?

[Tony Hwang]

Hi,
LED's another benefit is it is fractional second faster coming upto full
brightness. In panic braking situation it can mean a difference for
avoiding the accident. LED is either on or off voltage is applied.

[cl...@snyder.on.ca]

The 2 volt drop at the plug indicates undesized wiring in the tow
vehicle or poor connections. I'd bet on a combination of the two. The
scotchlock connectors used by most installers are CRAP and make a high
resistance connection - and most cars are wired barely heavy enough to
handle the OEM lighting load.

As for the extra drop to the lamps on the tailer, most likely ground
issues - 2.5 ohms on a 12 volt 36 watt tail lamp circuit (3
amps)will cause a voltage drop of 7.5 volts, so if you DO have a 2.5
ohm resistance in the ground the trailer has to be getting part of
it's ground through the ball hitch.. I'd take a set of good booster
cables from a good clean spot on the trailer frame to a good clean
spot on the tow vehicle frame and see what it does for your voltage at
the bulb.

[Jon Danniken]

On 08/16/2013 04:39 PM, DerbyDad03 wrote:
>
> The LED route is where I'm headed which is why I was checking out the
> wiring, just making sure everything was OK. I'm looking at LED replacement
> that will plug into my existing bulb socket.
>
> This 1157 replacement bulb says it will run at 7.5 - 14 V
>
> http://www.ledtrailerlights.com/stt/stt_1157.htm
>
> The marker units say they'll run at 9 - 16 V
>
> http://www.ledtrailerlights.com/cm/00-4400.htm
>
> However this complete unit, which plugs into the 1157 socket, doesn't list
> a voltage range.
>
> http://www.ledtrailerlights.com/stt/led-insert.htm
>
> I'm guessing the complete unit will be brighter than just the bulb, and I'm
> guessing it'll run at the 9.5 V I have at those fixtures, but I'll have to
> call the vendor to find out for sure.
>
> I'm assuming that LED's have one brightness. In other words, any voltage
> above the minimum produces the maximum brightness, correct?

No; you can make an LED barely come on, or you can run it with too much
current and it will get brighter than specified. Too much current and
you burn it out (heat death), in an amount of time that depends on the
excess amount of current. There is a threshold for them to begin to
come on at all though, at which point they are still dim, while an
incandescent has an infinite amount of dimness (down to zero).

There do exist current-limiting circuits for LEDs; I have one in my
headlamp that keeps the LED at a constant state until the battery drops
down below the threshold needed to maintain the illumination level.

As far as taillight assemblies go, my experience is that the unit I got
works great at the 9.5VDC that I got from my original converter (the new
one puts out 11.3VDC). I'm sure it would be brighter if I fed it 12VDC,
but it put out more than enough light at 9.5VDC, and far more than
incandescents at that voltage (which were barely discernable), which is
why I switched.

Jon

[cl...@snyder.on.ca]

Not technically. The more current through a LED the more light - but
good LED LAMPS use driver circuits that control the current. This
makes your assumption relatively close to true - for quality lamps
(but those are not terribly common on the market - you pay your money
and you take your chances.

[Nate Nagel]

2.5 ohms is a lot when you're talking about 12V systems; V=IR so if you
are pulling an amp or more (extremely possible, unless you are using LED
lighting on your trailer) that's a 2.5 volt drop right there. Time to
break out the deoxit, abrasive of choice, and some grease...

if the trailer is steel you might want to just go ahead and run a ground
wire connecting all the ground points together.

nate

[Nate Nagel]

Better ones that have a proper driver, yes. Don't use LED replacement
"bulbs" instead use dedicated LED lighting assemblies. The latter are
far superior in every way, are likely available as sealed units (in case
you are talking about a boat trailer where the lights may be submerged
when launching) aren't significantly more expensive, and are fully legal
for road use.

This or something similar should work well

https://www.truck-lite.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=59003&langId=-1

Peterson, Grote, etc. are also good brands to look at - whatever your
local boat supply, truck parts store, etc. has in stock. Any of those
manufacturers should have a selection of surface mount, flush (snap in
gasket) round, flush oval, whatever you need.

nate

[cl...@snyder.on.ca]

On Sat, 17 Aug 2013 09:36:42 -0400, Nate Nagel <njn...@roosters.net>
wrote:

I think he said it is aluminum - and tying all the clearance lights
together would be a major job..

[DerbyDad03]

I can't use the type of tail lights that you linked to. My tail lights are
built into the rear doors, which is why I provided the link to this
fixture...

http://www.ledtrailerlights.com/stt/led-insert.htm

It replaces my current lens and plugs into the 1157 bulb socket.
Unfortunately, it's one of the few LED products on that website that
doesn't list the operating voltage range. I'll be giving them a call soon
to find out.

As a side note, the kit you linked to includes those Quick Splice
connectors. Those belong in the same container as back stab receptacles -
the trash container.

[DerbyDad03]

My entire post was part of your response and is part of this one.

I'm not sure what made you think I said it was aluminum.

[Nate Nagel]

oh yeah, if you're going to splice, use proper solder and heat shrink,
or else proper plug in connectors... I just ASSumed that nobody
actually used those things.

can you post a pic of your current taillights? I bet there is a drop in
LED full fixture replacement available unless they're real odd, which is
really the best way to go... they'll last you another decade at least.

nate

[DerbyDad03]

On 8/17/2013 6:47 PM, Nate Nagel wrote:
> On 8/17/2013 1:43 PM, DerbyDad03 wrote:
>> Nate Nagel <njn...@roosters.net> wrote:

...snip...

>>> This or something similar should work well
>>>
>>> https://www.truck-lite.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10001&storeId=10001&productId=59003&langId=-1
>>>
>>>
>>> Peterson, Grote, etc. are also good brands to look at - whatever your
>>> local boat supply, truck parts store, etc. has in stock. Any of those
>>> manufacturers should have a selection of surface mount, flush (snap in
>>> gasket) round, flush oval, whatever you need.
>>>
>>> nate
>>
>> I can't use the type of tail lights that you linked to. My tail lights
>> are
>> built into the rear doors, which is why I provided the link to this
>> fixture...
>>
>> http://www.ledtrailerlights.com/stt/led-insert.htm
>>
>> It replaces my current lens and plugs into the 1157 bulb socket.
>> Unfortunately, it's one of the few LED products on that website that
>> doesn't list the operating voltage range. I'll be giving them a call soon
>> to find out.
>>

...Snip ...

>
> can you post a pic of your current taillights? I bet there is a drop in
> LED full fixture replacement available unless they're real odd, which is
> really the best way to go... they'll last you another decade at least.
>
> nate

There's a link to a pic included below.

Follow this 4-step logical progression and tell me if you think it makes
sense. Obviously a call to Bargman should clarify everything. I plan to
call them on Monday.

1 - The part number on my fixture is 30-84-022, which tells me it's an
84 series fixture.

http://i440.photobucket.com/albums/qq121/DerbyDad03/BargmanTaillight_zps9942fb32.jpg

2 - I found an RV forum where a poster said he replaced his 30-84-022
with a 47-86-101 LED fixture and that it was an exact fit. I've looked
at the Bargman site and it looks like the 47-86-101 should work, but
mine is an 84 series, so I'm not sure.

http://www.bargman.com/content/products.aspx?lvl=3&parentid=0&catID=8220&part=48-86-101

3 - The replacement part listing for the 47-86-101 shows just the LED
lens with a part number of 47-84-420. Note the "84". This is just the
LED lens with bare wires.

http://www.bargman.com/content/products.aspx?lvl=3&parentid=0&catID=8220&part=47-84-420

4 - Bargman also makes a "upgrade" LED lens with an 1157 plug that fits
the existing socket in my 30-84-022. The part number is 42-84-410.

http://www.bargman.com/content/products.aspx?lvl=3&parentid=0&catID=8220&part=42-84-410

My conclusion:

If the replacement LED lens (47-84-420) for the full replacement LED
fixture (47-86-101) is nothing more than the upgrade LED lens
(42-84-410) without the 1157 plug, it would be a waste of time for me to
replace the entire fixture and have to wire it in. As long as the socket
is in good shape, why shouldn't I just buy the upgrade LED lens? Two
screws, a "bulb twist" and I'm done.

Am I'm missing anything in that thought process?

Thanks.

[bob haller]

I would buy ONE and just try it......

Although if the trailer is older I would just rewire it, add dedicated ground wires to not only the trailer but the tow vehicle, with proper soldered wires and heat shrink tubing.....

like i said if the traier is older sometimes its best to start over...

the side marker lights arent as likely to have wiring troubles since most of the wiring is up high away from rain water and deicing chemicals.... but still replace them with Leds. Look at this as a one day interesting project. while your at it fix anything else thats broke or failing like hinges and locks, and check the underside and roof for rust, and check the ires if they are old replace them and repack the wheel bearings.... while checking the trailer jack and restraint chain/////

a few years ago a tree chipper trailer came loose and killed 3 or 4 people...

maintence is key to safe operations
I found one trailer with flakey lights where much of the wiring was rotting away. undoubtedly from salt water exposure

[DerbyDad03]

bob haller <hal...@aol.com> wrote:
> I would buy ONE and just try it......
>
> Although if the trailer is older I would just rewire it, add dedicated
> ground wires to not only the trailer but the tow vehicle, with proper
> soldered wires and heat shrink tubing.....

Other people have mentioned the tow vehicle ground. I have a question...

My tow vehicle has a factory installed connector in the wire harness for
the trailer wiring. This cable and converter plugs right into that
connector.

http://www.etrailer.com/Custom-Fit-Vehicle-Wiring/Tow-Ready/118336.html

With that setup do I need to be concerned about the vehicle ground or
anything else related to the vehicle wiring? Is it (normally) safe to
assume that the factory installed harness is properly wired?

>
> like i said if the traier is older sometimes its best to start over...
>
> the side marker lights arent as likely to have wiring troubles since most
> of the wiring is up high away from rain water and deicing chemicals....
> but still replace them with Leds. Look at this as a one day interesting
> project. while your at it fix anything else thats broke or failing like
> hinges and locks, and check the underside and roof for rust, and check
> the ires if they are old replace them and repack the wheel bearings....
> while checking the trailer jack and restraint chain/////
>
> a few years ago a tree chipper trailer came loose and killed 3 or 4 people...
>
> maintence is key to safe operations
> I found one trailer with flakey lights where much of the wiring was
> rotting away. undoubtedly from salt water exposure

I'm way ahead of you, Bob!

The lights were the last task in my periodic maintenance exercise. The
tires are fine and inflated to proper pressure - including the spare, the
wheel bearings were repacked, the hinges and other hardware were removed,
wire wheeled and coated with RustOleum Cold Galvanizing Compound and the
fenders were removed painted. While the trailer was on the jack stands I
inspected the underside, the axle, etc. I checked the safety chains and
their connection at the trailer. It all looks good.

Funny story about the jack. I've been using a wheeled jack for years. It
sure makes it easy for me to move the trailer around in my driveway. A few
years ago I found that after I swung the wheel down, it would hold the
trailer up but as soon as I tried to move it, the jack would start to
collapse. Turns out that the nut end of one of the carriage bolts that
holds the jack to the pivot plate had sheared off and the part that was
left just barely caught. It was fine while in the vertical or horizontal
position, but as soon as any lateral force was put on the bolt, it shifted
just enough to move out of the pivot plate and cause the jack to collapse.
You couldn't tell that the bolt was sheared unless you stood directly over
the jack and looked down into the space where carriage bolts came out of
the back of the pivot plate. It all looked good from the outside. It's now
one of the things I check on a regular basis.

So, now, the only thing left to deal with are the lights. My only real
concern is the brightness of the tail lights. Rewiring has long been on my
list of things to do, but if an LED upgrade will improve the tai lights,
I'll be satisfied for now. I've got an 900 mile round trip to my daughter's
college in a couple of days and don't have time to rewire the trailer
before then. If the LED's are brighter with the existing wiring, then
they'll already be there when I get around to the rewire.

It's going to happen, I just can't say when.

[bob haller]

try running a wire directly from the tow vehicles battery ground to the trailers frame..... and the ground terminal of the plug....

if the lights get brighter then the ground is a issue and best fixed before you leave....

you could run a semi permanent ground wire for this trip till you fix it permanetely. some contact cleaner on all parts of the plug cant hurt.

taske a close look at the 2 parts contacts, they may be eroding away...

[woodchucker]

On 8/16/2013 7:39 PM, DerbyDad03 wrote:

So unless you have a new trailer, why not just replace the whole socket
assembly. Sockets deteriorate over time. Some of the new lights are much
nicer than putting a plug in bulb in. They over more leds so if one
fails you still have others.

--
Jeff

[DerbyDad03]

I spent some quality time with the trailer today and here's what I found.

First, the replacement 1157 LED bulbs didn't work very well. It's not
that weren't they bright enough, the problem was the directionality. The
socket inside the fixture is positioned such that the bulb "lays flat"
as opposed to pointing straight out. The incandescent 1157 bulbs spread
the light across the entire lens. The LED bulb acts more like a
flashlight, only lighting up 1/4 of the lens in the direction it points.
In fact, my wife thought the LED side was out until she stood directly
behind the trailer. While the section that was lit was a little bit
brighter than the incandescent, she said she would rather be following a
trailer with the incandescent than the LED. I also tested it at night
and about 3/4's of the lens was lit up, but there was still a dark void,
unlike the incandescent who's lens was fully lit.

OK, so now I decided to look into the ground situation.

Just so you know what I'm working with, the trailer has the following
set up:

- Six GE193 side markers, which are grounded via the screws that hold
them into the trailer shell

- One GE193 license plate light, which is grounded via a pigtail to a
self tapping screw into a trailer frame member.

- Two 1157 (dual filament) tail/blinker/stop lights. The left side is
grounded via a pigtail to the same self tapping screw as the license
plate light and the right side is grounded via a pigtail to a self
tapping screw into a trailer frame member on the other side of the trailer.

- One 1156 (single filament) bulb for an interior light in a switched
fixture which is grounded via a pigtail to the same self tapping screw
as the right tail light.

The following tests were all done with the trailer disconnected from
the tow vehicle hitch to eliminate the hitch connection from the
equation. The only connection was the vehicle flat four to the trailer
flat four. The vehicle flat four cable is attached to a factory
installed connector in the vehicle's wiring harness and uses this cable
and converter:

http://www.towready.com/content/products.aspx?lvl=3&parentid=1500&catID=1505&part=118336

When I started testing, I had removed the LED bulbs and the tail light
sockets were empty. The side markers, license and interior bulbs were
all installed.

The first thing I did was disconnect the ground wire that went from the
trailer's flat four to the trailer's tongue, removing the trailer's
frame as the ground. I ran a dedicated ground wire from the trailer's
flat four to one of the rear tail light assemblies. When I turned the
tow vehicle lights on, the voltage read 12.85 V at that tail light.
Obviously, no lights came on because there was no bulb in the tail light
socket and the rest of the lights had no ground.

I then ran a pigtail from the tail light's ground to the ground screw at
the rear of the trailer that normally supplies the ground for that tail
light and the license plate light. That screw goes into the frame of the
trailer. When I did that, the side markers and license plate lights came
on and the voltage at the tail light dropped to about 11 volts. When I
inserted the tail light bulbs, the voltage dropped to the 9.5 V that I
had been reading without the dedicated ground.

That tells me that whether I use a dedicated ground from the flat floor
to the tail lights or use the frame as the ground path, I'm still going
to get that voltage drop.

I then ran a dedicated ground directly from the battery's negative
terminal to the tail light. There was no improvement. 12.85 volts with
no bulb in the tail light socket and the rest of the trailer not
grounded. As soon as I added a pigtail to the trailer frame, the voltage
dropped almost 2 volts. Then when I put the tail light bulbs back in, I
was down to the 9.5 level.

I went around the trailer pulling side marker bulbs and each time I
pulled a bulb the voltage at the tail light went up by 0.2 - 0.5 volts.
It was not consistent which tells me that each bulb was drawing a
slightly different amount of current.

I think the next test is going to be to start running dedicated grounds
to each fixture and see what happens. Since each fixture that uses the
trailer frame as ground added to the voltage drop, there doesn't seem be
a single cause for the drop, i.e. it's not one bad fixture causing the
problem.

Heck, as long as I'm running all those grounds, I might as well just
rewire the whole trailer. Running the extra ground wire to the side
markers won't be that hard, but since the current ones are single wire
fixtures with self tapping screws, I'll either need to use a nut, bolt
and lug for the ground or replace the side markers with 2 wire fixtures.

I just wish I knew before I started rewiring whether or not a dedicated
ground to each fixture is really going to resolve the voltage drop
issue. Running a temporary ground wire is as much a pain as rewiring
since there is really is no good way to attach the ground to the current
side markers unless I make up bunch of clip leads and clip the ground
to the ground bracket on the housing.

Maybe I should just do all my driving at night. The lights are easy
enough to see when it's dark.

[cl...@snyder.on.ca]

I doubt the ground is the problem, given the tests you have done. What
is the voltage from the tail-light connection to ground when the
lights are lit? If it is 9.5 volts, the problem is in the tow vehicle
wiring. Use voltmeter from the connected trailer plug to the
tail-light on the car. If over 1 volt (I like to see less than .2) the
problem is in the trailer wiring connections. If voltage at the tow
vehicle tail light is also low with the trailer connected it is a
problem with the main tow vehicle wiring.

[John G]

DerbyDad03 explained on 19/08/2013 :

> On 8/18/2013 10:19 AM, bob haller wrote:
>> try running a wire directly from the tow vehicles battery ground to the
>> trailers frame..... and the ground terminal of the plug....
>>
>> if the lights get brighter then the ground is a issue and best fixed before
>> you leave....
>>
>> you could run a semi permanent ground wire for this trip till you fix it
>> permanetely. some contact cleaner on all parts of the plug cant hurt.
>>
>> taske a close look at the 2 parts contacts, they may be eroding away...
>>
>
>
> I spent some quality time with the trailer today and here's what I found.
>
> First, the replacement 1157 LED bulbs didn't work very well. It's not that
> weren't they bright enough, the problem was the directionality. The socket
> inside the fixture is positioned such that the bulb "lays flat" as opposed to
> pointing straight out. The incandescent 1157 bulbs spread the light across
> the entire lens. The LED bulb acts more like a flashlight, only lighting up
> 1/4 of the lens in the direction it points. In fact, my wife thought the LED
> side was out until she stood directly behind the trailer. While the section
> that was lit was a little bit brighter than the incandescent, she said she
> would rather be following a trailer with the incandescent than the LED. I
> also tested it at night and about 3/4's of the lens was lit up, but there was
> still a dark void, unlike the incandescent who's lens was fully lit.

You have just demonstrated why a lot of these after market lamp
replacements, particularly LEDS are not certified for use on the road
in most counties of the world.

On top of that at least some countries require WIRE ground connections
back to the vehicle .
The tow ball is not accepted as a connection.

I doubt adding wire grounds will fix the problem.
As I see it you still have a single bad connection and every lamp you
add increases the drop.
You should be able to measure the drop across each connection (less
than a volt) then one of them will be higer and you have got your
culprit.

--
John G

[DerbyDad03]

<cl...@snyder.on.ca> wrote:

...snip...

>
>
> I doubt the ground is the problem, given the tests you have done. What
> is the voltage from the tail-light connection to ground when the
> lights are lit? If it is 9.5 volts, the problem is in the tow vehicle
> wiring. Use voltmeter from the connected trailer plug to the
> tail-light on the car. If over 1 volt (I like to see less than .2) the
> problem is in the trailer wiring connections. If voltage at the tow
> vehicle tail light is also low with the trailer connected it is a
> problem with the main tow vehicle wiring.

Please clarify what you mean by "use a voltmeter from the connected trailer
plug to the tail light on the car".

From what pin on the trailer plug? To what on the tail light on the car?

And if the problem is with the tow vehicle wiring, what is the problem?
What would I be looking for if the voltage you want me to check is over 1
volt?

[DerbyDad03]

It's too late to work on anything now, but I wonder what would happen if I
applied 12 volts from a fully charged battery pack like this...

http://britfa.gs/mph/src/133675951130.jpg

If I don't see a voltage drop with that, then it must be the tow vehicle,
right?

[bob haller]

try connecting a positive wire to a positive socket connection for he tail light .....

your problem is likely a bad plug assembly, a direct connection from the battery positive should brighten things.....

in fact the one connection will likely brighten all lights

trailer plugs are cheap, you could make up a test plug with light bulbs, and plug it into the tow vehicle......

or make up a test tow vehicle end connection to power the trailer, add a switch or two to duplicate brake lights etc

but i would still suggest rewiring the total trailer, you will find troubles, corroded contacts, poor connections, and in the case of one trailer i worked on the main traler wire insulation was badly worn, in a hidden area it would of shorted and taken out all trailer lights..... found when pulling new cable.

if you rewire go at least one size heavier......

if the wire is 16 gauge, go to 14 gauge, it will be stiffer, but work better...... of course use straded

the last trailer i worked on, the trailers plug assembly connected inside a small metal box on the frame. taking the cover off revealed its backside was rotted out, allowing water coirrosion of the connections....'the damage wasdnt visible from the outside

you should seal all crimps with blobs of silicone caulk all around every connection so water cant get at them....

[Tony Hwang]

Hmm.
Souns like a inadquate wire size or poor connections; crimping, screwed
down with star washer, rust causing poor conductivity, etc. I don't know
how old the trailer is. When I had my fiver, I used to inspect wiring at
start of every camping season. if something is ??? I remedied
it. And LED needs good diffuser lens, reflector to be effective. LEDs
comein many different forms, shapes, specs.

[Tony Hwang]

Hi,
Right on. Ohm's law. Poor connections in DC circuit act like a diode.

[Tony Hwang]

Hi,
Dielectric Si grease is even better.

[DerbyDad03]

Thanks for the suggestions. The most that will happen this week will be a
possible test with an external 12 V source, or perhaps a different tow
vehicle if I can get someone with a flat four connector to stop over. That
would at least eliminate my tow vehicle as the issue.

The trip to my daughter's college is on Wednesday and as long as everything
is working at this point, I'm not messing with any wiring on the trailer or
tow vehicle so soon before the trip.

Thanks again.

[cl...@snyder.on.ca]

On Mon, 19 Aug 2013 14:34:43 +1000, John G <gree...@ozemail.com.au>
wrote:

It is not accepted in Canada either - don't know about the USA.

[cl...@snyder.on.ca]

From the wire that feeds your taillights at the plug to any of your
tail-lights on the tow vehicle. You want to do a "voltage drop" test.
It will show if there is resistance between where the tow vehicle
tailights get their power and where the trailer gets it's power -
which boils down to the adapter wiring. If you have no voltage drop
there, check the voltage from ground to the tow vehicle tail light -
if the voltage is low there, you have bad wiring or a bad switch in
the tow vehicle.

On MOST cars without a trailer towing package, you are smart to
install a relay box (or electronic equivalent)) and feed it with a #6
wire from the battery (fused) and have the tail lights, signals, and
brake lights on the trailer fed by the relays, and the relays turned
on by the equivalent circuit on the tow vehicle. You can put the relay
on the tow vehicle, or if you also run a live feed to the trailer, you
can put it on the trailer (which means it is good for more than 1
vehicle, but any tow vehicle MUST have a live feed to the trailer)

Good idea also to have the live feed relayed so it is only on with the
ignition to prevent power leakage and corrosion in the circuit - and
having a switch so you can disconnect the power to the hitch is also a
good idea (again, so nothing is live back there to encourage corrosion
when not connected to the trailer)

[cl...@snyder.on.ca]

It would tell you if you had wiring trouble on the trailer. If it
works from the pack, the trailer is A-OK - ready to go. Don't waste
time on the trailer, look at the tow vehicle.

[cl...@snyder.on.ca]

One thing that you need to remember when testing trailer lights.
If the lights go "wonky" when you use the signals you have a bad
ground - period. Signals on, tail lights off, and side markers glowing
with the signal? Bad ground. Period. Bad TRAILER ground - not bad lamp
ground, most likely - and if it is a bad lamp ground it will be on the
lamp that causes the interaction.. If the signal can't get a good
ground it will back feed through the tail lamp filament, which will
eventually find a ground through the tail lights of the tow vehicle -
making the low wattage side markers glow.

If there is no interaction between signals and other lamps you can be
99.999% sure it is NOT a ground problem. If there is interaction,
99.9999% sure it is.

[DerbyDad03]

<cl...@snyder.on.ca> wrote:
> On Mon, 19 Aug 2013 04:42:33 +0000 (UTC), DerbyDad03
> <teama...@eznet.net> wrote:
>
>> <cl...@snyder.on.ca> wrote:
>>
>> ...snip...
>>>
>>>
>>> I doubt the ground is the problem, given the tests you have done. What
>>> is the voltage from the tail-light connection to ground when the
>>> lights are lit? If it is 9.5 volts, the problem is in the tow vehicle
>>> wiring. Use voltmeter from the connected trailer plug to the
>>> tail-light on the car. If over 1 volt (I like to see less than .2) the
>>> problem is in the trailer wiring connections. If voltage at the tow
>>> vehicle tail light is also low with the trailer connected it is a
>>> problem with the main tow vehicle wiring.
>>
>> Please clarify what you mean by "use a voltmeter from the connected trailer
>> plug to the tail light on the car".
>>
>> From what pin on the trailer plug? To what on the tail light on the car?
>>
>> And if the problem is with the tow vehicle wiring, what is the problem?
>> What would I be looking for if the voltage you want me to check is over 1
>> volt?
> From the wire that feeds your taillights at the plug to any of your
> tail-lights on the tow vehicle.

I assume that you want these readings taken without the trailer plugged in.


The reading is between 0.071 and 0.084 V. It varied each I started the van
and varied from side to side.

> You want to do a "voltage drop" test.
> It will show if there is resistance between where the tow vehicle
> tailights get their power and where the trailer gets it's power -
> which boils down to the adapter wiring. If you have no voltage drop
> there, check the voltage from ground to the tow vehicle tail light -
> if the voltage is low there, you have bad wiring or a bad switch in
> the tow vehicle.

I checked it using both grounds, the ground on the flat four and the ground
at the bulb socket. 13.24 volts at the tail light using both grounds. 13.3
volts at the flat four plug using both grounds.

Resistance reading from tail light ground to flat four ground with the tail
light bulb out reads 0.5 ohms.

Seems to me that the problem is in the trailer, correct?

[k...@attt.bizz]

On Fri, 16 Aug 2013 16:30:55 -0700, Tony Hwang <drag...@shaw.ca>
wrote:

>Jon Danniken wrote:
>> On 08/16/2013 11:34 AM, DerbyDad03 wrote:
>>> I'm reading a voltage drop in my trailer wiring and wondering if it's
>>> normal.
>> [snip]
>>
>> Ralph provided a pretty good answer, so there is no need to repeat what
>> he already stated.
>>
>> I will add, however, that I noticed a sizeable drop on my 5-way to 4-way
>> adaptor, which I ascribed to a typical voltage drop due to
>> semiconductor(s) (diode and/or transistor) in the adaptor.
>>

>Hi,
>Typical Si junction voltage drop in semiconductor is ~0.2 Volts.

Si junction drop is considered to be .6V-.7V but diodes can easily
drop over 1V at higher currents. Perhaps you're thinking about
Schottky diodes? They're closer to .3V at very low currents and
perhaps .7V at higher currents.

[Tony Hwang]

Hi,
Automotiv DC wiring is no place for Schottky diodes.

[k...@attt.bizz]

On Tue, 20 Aug 2013 17:23:13 -0700, Tony Hwang <drag...@shaw.ca>

Wrong again. They're *often* used in automotive wiring. Battery
isolators *ARE* SBDs (and will drop 1V at high currents).

[Tony Hwang]

Hmm,
I wouldn't use other than SiC type.

[k...@attt.bizz]

On Tue, 20 Aug 2013 18:28:47 -0700, Tony Hwang <drag...@shaw.ca>

You obviously know nothing about the subject.

[Tony Hwang]

Hi,
Please enlighten me kindly explaining junction type, doped type
and SiC type? Was Schottky German or Hungarian?

[k...@attt.bizz]

On Wed, 21 Aug 2013 21:09:53 -0700, Tony Hwang <drag...@shaw.ca>

Good Lord, you really must prove that you're a total moron. No need
to use terms you don't understand. We got it.

[Jon Danniken]

On 08/19/2013 06:31 AM, DerbyDad03 wrote:
>
> Thanks for the suggestions. The most that will happen this week will be a
> possible test with an external 12 V source, or perhaps a different tow
> vehicle if I can get someone with a flat four connector to stop over. That
> would at least eliminate my tow vehicle as the issue.
>
> The trip to my daughter's college is on Wednesday and as long as everything
> is working at this point, I'm not messing with any wiring on the trailer or
> tow vehicle so soon before the trip.

What happened with the LED panel idea? There was one that plugged in
like a bulb to feed an array of what looked like a dozen or so LEDs.

Jon

[DerbyDad03]

The LED lens is still a viable option. I didn't have time to get a set via
mail order nor call the "trailer stores" in my area, mainly because they
are not that close to me. I've been too busy working, getting ready to move
my daughter and testing the trailer wiring to drive to one of the 2 places
that might carry the replacement lens. I didn't even bother to call because
I knew I wouldn't have time to go buy them. I'll call when I get back.

I did check 2 local auto stores but all they carried was the 1157 LED
bulbs, which didn't work out so well.

BTW...my daughter's move went fine. She's in her apartment and I'm taking
the long way home, stopping to visit some old friends for a day or two.

I'll update the LED lens situation after I get a set to try.