Tail Lights Blow Fuse: Please Help!
mary wilkins
working. When I changed the fuse (which was blown) that is under the
driver's side, under the steering wheel, the lights came on for just a
second, and then the fuse was blown again.
I am not sure how to fix this!? Should I check each light bulb for
corrosion? bad wiring? water? and then what?
I really love my car, and would like to keep it...but I am in the dark
about this one!!
Thanks for any advice!
Mark Olson
You've probably got insulation scraped off one of the taillight circuit
wires where it goes through a hole in the body, trunk lid, etc. What I
like to do is connect an old headlight bulb in place of the fuse. Make a
connector out of a blown fuse and wire up to that, and plug the modified
fuse into the taillight fuse location.
The headlight bulb will glow brightly while the short is present- wiggle
the taillight circuit wires until the bulb goes out or glows dimly, and
you know you've found the offending spot.
Note that you have to use a bulb that draws more than the taillights do
in order for this to work- a #194 instrument lamp bulb won't tell you
anything since it's small compared to the load drawn by one or more
taillight bulbs.
Tim Wescott
You have a short circuit somewhere. It's not horribly bad or the lights
wouldn't have come on at all -- you'd just see the fuse blink and that
would be it.
If you're lucky one of the bulbs has burnt out in such a way that it's
shorted. If you're not, then the most likely culprit is that one of the
tail light wires has rubbed off some insulation and is touching metal
(although this isn't terribly consistent with the "goes on for a moment"
bit).
If you have a meter, turn off the lights, connect the meter between the
tail light power and ground, and check the resistance. Then mess with
things.
If you don't have a meter, get some fuses and mess with things.
Remove all the bulbs.
Check the meter and note the resistance to ground. Barring oddball
wiring, it should be very high (certainly over 100 ohms, probably in the
tens or 100's of thousands). If you don't have a meter, plug in a fuse,
turn on the lights, see if the fuse survives. If it does, get new bulbs.
If that doesn't fix it, inspect the wires from the tail lights
_carefully_. Look for worn insulation somewhere -- without looking all I
can say is to see if there's a projecting metal bracket that may have
scrubbed off some insulation. With the meter you can wiggle/tug/pull on
the wires while watching the reading -- if the resistance to ground
suddenly gets high then you're hanging onto the wire with a problem. If
it gets high and _stays_ high you're not done -- you need to find the
short and fix it, 'cause you don't want your tail lights crapping out at
rush hour during a rain storm.
Once you've found the worn spot, wrap it with electrical tape, and if it
seems indicated maybe try to hold the wire down so it won't rub on
whatever rubbed it raw in the first place.
Good luck -- finding short circuits is a PITA.
Paul
That is an excellent idea! Thanks.
Steve Austin
Trailer hitch?
Scott Dorsey
>My Toyota Sienna 98 no longer has tail lights. All other lights are
>working. When I changed the fuse (which was blown) that is under the
>driver's side, under the steering wheel, the lights came on for just a
>second, and then the fuse was blown again.
>
>I am not sure how to fix this!? Should I check each light bulb for
>corrosion? bad wiring? water? and then what?
Something is shorted to ground somewhere. Disconnect the tail light wiring
and remove the bulbs. Put a new fuse in and hit the brakes. Does the fuse
blow?
>I really love my car, and would like to keep it...but I am in the dark
>about this one!!
Somewhere, either before or after the tail light switch, the tail light
wire is touching the car chassis. First find out if it's before or after
the switch, then find out if it's in the lamp holders itself.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
hls
"Mark Olson" <ols...@tiny.invalid> wrote in message
news:ib2dnTRTi4WtiaHW...@posted.visi...
I like this approach.. It is safe, and will give you a simple and positive
indication to help you troubleshoot the system.
If a beginner tries to use a voltmeter or ohmmeter, he or she can get
confused easily. Using this approach, you cant blow the system or
misinterpret what is happening.