[GMCnet] Need Help With Airbag Controls/Compressor

[Bryan Hartman]

Hello Everyone Summer is approaching and I am trying to get a few of the issues sorted out on the coach. Most of the big stuff I am going to pay the
experts to do but there are a few things I need to get sorted out so I can get the coach to the shops I want to use. The first one is to get the
compressor for the airbags working again. I am a relative newbie with working on these coaches so I hope the experts on the forum can help me out.

Here is the situation:
When I bought the coach, the system was working fine. The bags were "older" but serviceable. I picked the coach up and drove it across the country in
the middle of summer with no issues. There may have been a very little air leakage but nothing noticeable and the raise/lower switches worked fine.
Shortly after I got the coach home, the compressor would go into "Raise" mode even though the switches were on "Lower". I would have to shut off the
engine and turn on a few times before it would self-correct. Now the switches do not work and the compressor will not turn on at all. I have just
lived with the annoyance for about a year since I have not done much more than day trips. I just top off the bags when I leave the house and I carry a
separate little compressor just in case. Over time then the system is leaking down quite a bit quicker and I am less comfortable taking her out even
for short trips. I have removed the switch panel and inspected the connections. They look good but I am going to pull apart and hit them with a wire
brush to be sure. I looked for an inline fuse near the compressor but I could not find one.

I was thinking I would just pull the compressor out and see if I could test it on the table. Any other ideas?

Thanks In Advance,
--Bryan


_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

[Johnny Bridges via Gmclist]

What system? Electro - Level? Electro - Level II? Something else?

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Billy Massey]

The problem is in the three rocker switches on the dash. Take them out one
at a time. Take them apart and carefully clean the contacts. Put a little
silicone grease where needed, reassemble and replace.

You'll be amazed
bdub

-----Original Message-----
From: Gmclist On Behalf Of Bryan Hartman
Sent: Saturday, March 04, 2017 1:28 PM

Here is the situation:
When I bought the coach, the system was working fine. The bags were "older"
but serviceable. I picked the coach up and drove it across the country in
the middle of summer with no issues. There may have been a very little air
leakage but nothing noticeable and the raise/lower switches worked fine.
Shortly after I got the coach home, the compressor would go into "Raise"
mode even though the switches were on "Lower". I would have to shut off the
engine and turn on a few times before it would self-correct. Now the
switches do not work and the compressor will not turn on at all. I have just
lived with the annoyance for about a year since I have not done much more
than day trips. I just top off the bags when I leave the house and I carry a
separate little compressor just in case. Over time then the system is
leaking down quite a bit quicker and I am less comfortable taking her out
even for short trips. I have removed the switch panel and inspected the
connections. They look good but I am going to pull apart and hit them with a
wire brush to be sure. I looked for an inline fuse near the compressor but I
could not find one.

I was thinking I would just pull the compressor out and see if I could test
it on the table. Any other ideas?

[Bryan Hartman]

Johnny Bridges wrote on Sat, 04 March 2017 12:05

> What system? Electro - Level? Electro - Level II? Something else?
>
> --johnny

Rats...I knew I would forget something. Pretty sure it is the Electro - Level. It is a '77 Palm Beach. It has one compressor and what looks like a
small air tank.


bdub wrote on Sat, 04 March 2017 12:06

> The problem is in the three rocker switches on the dash. Take them out one
> at a time. Take them apart and carefully clean the contacts. Put a little
> silicone grease where needed, reassemble and replace.
>
> You'll be amazed
> bdub

Thank you sir...On my way to try and I will keep you posted.

[Johnny Bridges via Gmclist]

Sounds like Electro-Level, same as mine. First check is fuse, there's one somewhere. Second is like bdub sez - switches. Disassemble, clean,
reassemble. Report back.

When the switches in mine go dixie (And it seems to be when, not if) I'll probably replace them with a piece of aluminum plate and three heavy duty
toggle switches from SkyCraft. One and dine. There's a zillion solenoid valves in there, each can be tested with 12 volts.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[gene Fisher]

Read here
http://gmcmotorhome.info/wireless.html

--
Gene Fisher -- 74-23,77PB/ore/ca
“Give a man a fish; you have fed him for today --- give him a URL and
-------
http://gmcmotorhome.info/
Alternator Protection Cable
http://gmcmotorhome.info/APC.html

[Bryan Hartman]

So I pulled apart the connectors, hit the posts with a wire brush, pulled all the female wires out of the connectors one at a time and transferred
them directly to the post on the switch. I wanted to make sure they each were tight... Nothing! %@#@@$##$%@$%

So then I went hunting after the elusive fuse and I can't find one anywhere. If my pea-sized brain has to pull out a multi-meter and start trying to
trace something I am done for...no idea what I am doing there.

How easy/reliable are the wireless air systems? Are there different versions? Pros vs cons?

Thanks everyone for all the replies.

[Billy Massey]

You have to take the switch apart. Not hust the connections. They are
rebuildable. There's a little metal clip on either end that has to spread
slightly for it to come apart. Use a sliver of fine emery cloth to clean
the contacts inside the switch.

[Ken Henderson]

Bryan,

Folks suggesting the switches didn't make it clear: You need to
DISASSEMBLE the switches! That's right, bend the tangs holding the rear of
the switch in place and CAREFULLY pull them apart, remembering where the
contacts and springs go. It's not as bad as it sounds, and that's the only
way you can clean out the 40 years old grease that's coagulated on the
contacts.

Ken H.

[Bryan Hartman]

Thanks Guys. I am off to clean the switches, the wonderful switches of mine.

[Emery Stora]

You should take apart the switches, not just the connectors. They gunk up inside and lose internal contact.

Emery Stora

[Bryan Hartman]

Switches removed, disassembled, cleaned, reassembled, and reinstalled.

Nada...Still not working. aggravating :(

[Nelson Wright]

Well, like Johnny Bridges said, first check the fuse. That would be located in the back of the glove box.

Sent from my iPhone
Nelson Wright

Orlando Fl.

[Bryan Hartman]

Thank you Nelson! With the knowledge of the mystery fuse's location, we have some progress. Fuse was blown so a new one is in. The Now with clean
switches and new fuse, every time I flip the switches I get a single "click" coming from from the compressor area and a quick draw on the system. Not
working yet be getting closer.

Nelson wrote on Sat, 04 March 2017 18:47

> Well, like Johnny Bridges said, first check the fuse. That would be located in the back of the glove box.
>
> Sent from my iPhone
> Nelson Wright

[Terry]

Check for power at the compressor while hitting the switch to raise. If there is power and ground at the motor but it is not running, you will have
found the/another problem and likely the fuse blower.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

[Ken Burton]

I hope I understand where you are at this point. I believe your compressor is not running at all.

If this is true, then you need to figure out whether the problem is with the compressor or the electric feeding it. The compressor is turned on by an
air pressure sensing switch mounted near the compressor inthe compressor cabinet. When the air pressure is low the switch pulls in and provides
+12VDC to the compressor. Find the air switch and remove the cover which is approximately 2.5" by 2.5". It is similar to a switch used on a stand
alone air compressor or a water well. There is nothing inside that will electrically hurt you. The maximum voltage in that cabinet is +12vdc.

The first thing I would do is turn on the key ignition key to the run position. You can start the engine if you want. Now check the switch and see
if it pulls in to start the compressor. If it is not pulled in, then press it in with your finger or a tool and see if the compressor runs. If it
does not run, then check with a meter or test light for +12 volts at the switch contacts. There are only 2 wires on that switch. I believe the power
supply to the switch is a 12 gauge brown wire. While you are there also check the -12 volt lead (ground) to the compressor motor.

If you want to temporarily apply +12 volts to the motor, look in the cabinet above the compressor and you will find +12 volts available on the house
fuses. You can jumper from there direct to the compressor. Use a 14 or 12 gauge jumper as that compressor draws around 20 amps.

I'll leave it there for now and see what you come up with. Depending on what you find I'll give you additional trouble shooting info in a follow up
posting.

You also said that you replaced the fuse. I am wondering if you got the correct location because that is suppose to be a 30 amp Circuit Breaker and
not a fuse feeding the compressor.

Good Luck. We will find your problem.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Bryan Hartman]

Thanks Ken. I Think the compressor is ok. I will jumper it to be sure.

The fuse I am talking about is right in the glove box where Nelson Wright told me it would be. It was the topmost fuse.

[Bryan Hartman]

She's fixed! I jumpered the compressor to confirm it was operational...it was. I then started looking back to make sure I reconnected everything
correctly. Oops! I had 2 of the three switches upside down(female ends still no back in connectors yet).

Now I just have to button everything back up and get new bags installed.

Thanks everyone!

[Johnny Bridges via Gmclist]

Love it when a plan comes together!

-0-johnny

--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Ken Burton]

bryhart wrote on Sun, 05 March 2017 15:08

> She's fixed! I jumpered the compressor to confirm it was operational...it was. I then started looking back to make sure I reconnected everything

> correctly. Oops! I had 2 of the three switches upside down(female ends still not back in connectors yet).
>
> Now I just have to button everything back up and get new bags ordered/installed.
>
> Thanks everyone!



Great!!

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Bryan Hartman]

Jinxed it. Switches were working well, compressor was coming on in manual and auto. I decided to give it and extended test so I manually inflated bags
with my air hose high enough to put some 2x4's under the coach. I lowered it down and let out most of the air from the bags. The plan was to pump up
and lower each bag manually one at a time using the compressor in the coach. I started with the left side. I flipped the switch, heard the compressor
fire up. I then went outside by the rear and had my 14 yr old son inside to operate the switches when it was time to stop/deflate. After 20-30 seconds
at the rear of the coach I hadn't seen any movement at all in the bag so I asked my son if he could still hear the compressor running. He listened and
said no. I went back inside and sure enough the fuse had blown. I replaced it again but now it just blows fuses as soon as I operate the switches.

Any ideas?

[Jim Kanomata]

Bob,
What year, and is it a electro level 1 or 2

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Bryan Hartman]

Also Jim, can you PM me? I am actually getting this road worthy to drive it down to you guys for some more extensive work. I was hoping to chat about
that if possible. Time, options, prices, etc...

Thanks,
--Bryan
--
1977 Palm Beach

[Charles Boyd]

Sir, that fuse is suppose to be a 30 amp resetting circuit breaker.
https://www.napaonline.com/en/p/BK_7823110




bryhart wrote on Mon, 06 March 2017 20:23

> Jinxed it. Switches were working well, compressor was coming on in manual and auto. I decided to give it and extended test so I manually inflated
> bags with my air hose high enough to put some 2x4's under the coach. I lowered it down and let out most of the air from the bags. The plan was to
> pump up and lower each bag manually one at a time using the compressor in the coach. I started with the left side. I flipped the switch, heard the
> compressor fire up. I then went outside by the rear and had my 14 yr old son inside to operate the switches when it was time to stop/deflate. After
> 20-30 seconds at the rear of the coach I hadn't seen any movement at all in the bag so I asked my son if he could still hear the compressor running.
> He listened and said no. I went back inside and sure enough the fuse had blown. I replaced it again but now it just blows fuses as soon as I operate
> the switches.
>
> Any ideas?

--
C. Boyd
76 Crestmont
East Tennessee

[Ken Burton]

C Boyd wrote on Mon, 06 March 2017 19:52

> Sir, that fuse is suppose to be a 30 amp resetting circuit breaker.
> https://www.napaonline.com/en/p/BK_7823110

Some additional comments here.

As you increase the air pressure in the tank, the compressor has to work harder and draws more current. Also if pressure is up in the tank when the
compressor starts, or the voltage is low when the compressor starts, it takes a little more current to get it started. Using the correct CB, or a
time delay (slow Blow) fuse, helps cover up these short term over current conditions.

So first do what Chuck suggests and get the correct CB. Second I would check and clean all of the connections in the motor cabinet both on the + 12
volts side and the ground side. Also check . One of the things I like to do as a quick check is: Get the compressor it running again. Then feel
all of the electrical connections, including the fuse / CB, for heat or warmth while the compressor is running. If a connection is warm (or hot),
then you have a problem and voltage loss there. It will only get warm when the compressor is running. You could also check connections with a
voltmeter but it will take you a little longer.

Finally, When the compressor is running, running the engine at the same time will raise voltage at the compressor motor and reduce it's current draw.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Bryan Hartman]

Thanks again everyone. I just want to make sure I understand. Here is the location in the glove box that I am referring to:

http://s148.photobucket.com/user/bryhart/media/GMC%20-%20Conroe%20TX%201977%20Palm%20Beach/1b9d0455-d56d-4674-9799-10ea64b83a39.jpg.html

Are you guys saying that that CB fits in the same slot? If so I believe you but I might need a picture so I understand.
--
1977 Palm Beach

[Terry]

Yes, there are circuit breakers that are just like the later model cars' ATC fuses but the blades are rolled into 2 small cylinders that snap into the
fuseholders for the glass fuses. Those fuseholder contacts in that pic need to be cleaned/polished for reliable operation.

--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.

[Bryan Hartman]

Thanks Terry. I will clean it all up when I reinstall!
--
1977 Palm Beach

[Ken Burton]

Terry, Thanks for helping him. I could not get that URL to display (Internet gremlins I guess) so I did not respond to him.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Ken Burton]

I finally got that picture to display.

Wow is that holder messed up.

You really need to clean that up. A slow turning dremel tool with a wire brush end might work. It really need to be clean. Also squeeze the
contacts a little bit to apply more tension on the CB. That may be your compressor problem if it is heating up during use.

[Billy Massey]

Chuck Boyd sent you a link to the breaker you need that includes a picture
of it.

On Mar 6, 2017 9:46 PM, "Bryan Hartman" > wrote:


Are you guys saying that that CB fits in the same slot? If so I believe you
but I might need a picture so I understand.

[John R. Lebetski]

1 Caig Deoxit D5 is what to use to clean fuse holder, switches and connectors.
2 Your switches may look "cleaned" and are still bad.
I'm pretty good at electrical/ electronic bench work and that one got me. There was a factory thin foam dust shield in the switches under the rockers
that has broken down to a non conductive goo balls material. These fragments are pin point small but can keep the points on switch from making
connection. Confirm all switch functions with a meter before reinstalling. Meter center to opposite from switch throw on each side then flip switch
and repeat as you would with any DPDT or DPDT center off switch.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[Bryan Hartman]

Billy Massey wrote on Tue, 07 March 2017 06:20

> Chuck Boyd sent you a link to the breaker you need that includes a picture
> of it.

Thanks. I see the picture I just can't picture how to install that thing in the slot I see in the fuse box. I was hoping for a picture of one of them
installed in the fuse box but maybe it will make more sense once I see it in person.

JohnL455 wrote on Tue, 07 March 2017 06:51

> 1 Caig Deoxit D5 is what to use to clean fuse holder, switches and connectors.
> 2 Your switches may look "cleaned" and are still bad.
> I'm pretty good at electrical/ electronic bench work and that one got me. There was a factory thin foam dust shield in the switches under the
> rockers that has broken down to a non conductive goo balls material. These fragments are pin point small but can keep the points on switch from
> making connection. Confirm all switch functions with a meter before reinstalling. Meter center to opposite from switch throw on each side then flip
> switch and repeat as you would with any DPDT or DPDT center off switch.

Thanks.

--
1977 Palm Beach

[Bryan Hartman]

Ok. Next update...I cleaned the terminals and installed the correct 30 amp circuit breaker. Flipped the switches and everything seemed to work
flawlessly. The compressor ran nonstop for 1-2 minutes and then shut off again. After that I could shut off engine, remove the CB from fuse box for 1
minute, reinstall, and flip the switches. The compressor would run for a few seconds and then the circuit breaker would trip. I waited about and hour
and retried. The compressor ran for 30 seconds and then it tripped again. I felt all the connections I could find and everything felt cool. The only
thing that was warm was the very top of the compressor.

thoughts?

[James Hupy]

The compressor motor is drawing more amps than your circuit breaker or fuse
is rated for. You either have high resistance in connectors between the
fuse and the motor of the compressor, corrosion in the conductors
themselves, or the mechanical components in the compressor are placing a
big load on the motor. ( ex. Broken rings, scored cylinder, etc.) Either
way, you need to investigate the amp draw, and resistance, and how
difficult it is to turn the compressor.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

[D C _Mac_ Macdonald]

Three possibilities that I see (off-hand) are compressor output line has blockage causing excessive current draw, wrong value (too low) of breaker/defective breaker, or simply aged, defective compressor!

Circuit breakers are mostly HEAT activated devices. Does IT get hot?


~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ Since 30 November '53 ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"




________________________________
From: Gmclist <gmclist...@list.gmcnet.org> on behalf of Bryan Hartman <bry...@gmail.com>
Sent: Tuesday, March 7, 2017 15:13
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] Need Help With Airbag Controls/Compressor

Gmclist Info Page - list.gmcnet.org<http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org>
list.gmcnet.org
To see the collection of prior postings to the list, visit the Gmclist Archives. Using Gmclist: To post a message to all the list members, send email ...

[Johnny Bridges via Gmclist]

I think your compressor wants looking at. It's heating up and something is binding... and at 40 years old, like to be anything in it. You might want
to disassemble it, clean it up and lube places where there's old hardened lube, and try it again. If you want to check connections, power it directly
from a battery. If you have an ammeter, hook it in line ans see what the current draw actually is.

--johnny

--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Bryan Hartman]

Thanks everyone. The brand new 30 amp CB does not feel like it is getting hot. I will start to work backwards from the compressor.

Question: If I disconnect the air line from the compressor should I make sure the air bags not inflated? Or is there some sort of "one-way" valve in
the system that would prevent it from losing pressure?

I don't know how to check from amperage draw or resistance but that is what youtube if for!
--
1977 Palm Beach

[Jim Kanomata]

Always check your ground and use a star type washer to get good contact.

--
Jim Kanomata
Applied/GMC, Fremont,CA
ji...@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502

[Scott Nutter]

Bryan,
Sorry to hear your having problems with the air system.
The compressure is relitavely new(within in 5 years). I don't know if it's the compressor. Can you get a psi reading at the tank when the pump kicks
off?
Maybe a solinoid is not opening.
Scott.
--
Scott Nutter
1978 455 Royale Center Kitchen, Quad bags.
Houston, Texas

[Bryan Hartman]

I will try that too.
--
1977 Palm Beach

[Bryan Hartman]

Scott - where do I get the reading from. Didn't see anything on the tank except for the very bottom. Looked like a drain though.

[Gary Kosier]

Bryan,

First thing to check is the filter on the inlet of the compressor.
They are a foam piece that disintegrates and gets sucked into
the compressor. Bad JuJu. John Clement has some synthetic
ones that are much better.

Gary Kosier
77PB w/500Cad
Newark, Ohio

--------------------------------------------------
From: "Bryan Hartman" <bry...@gmail.com>
Sent: Tuesday, March 07, 2017 8:06 PM

To: <gmc...@list.gmcnet.org>
Subject: Re: [GMCnet] Need Help With Airbag Controls/Compressor

[Scott Nutter]

Bryan,
I can't remember if it's a drain or drain/pressure relief valve. What I would do,as I'm doing now, is to put shut off valves with a air intake
valve(schrader valve) at the bags. Pump up the bags at the new air valve, and run it like that until you have time to trouble shoot more. You can pump
it up from outside the coach to get the proper ride height. Your bags are also fairly new, so they should hold the pressure for at least two weeks I
would think. I also installed a air pressure gauge at the bags. Then I just add air as needed to maintain ride height.
Please call me if I can be of help. I can email pictures if needed. I still have a systems monitor headed your way. The delay is due to old timers
disease!!

Scott.
--
Scott Nutter
1978 455 Royale Center Kitchen, Quad bags.
Houston, Texas

[Bryan Hartman]

Thanks Scott. I wasn't sure of the age of the air bags. I looked at them (being and old tire guy) and was not comfortable with the amount of
"cracking". It might just be cosmetic but it looked like I could see the carcass in some of the bigger ones. I went ahead and ordered 2 new bags with
the shut-off valves from Applied. Once I have those installed I can spend a bit of time working out the kinks, wonks, & leaks. If it is still giving
me issues after the good ol' college try I might consider the wireless air system (but that is a bit downstream).

No worries about your "disease"...I think I might share your affliction.

--
1977 Palm Beach

[Bryan Hartman]

Ok. The new air bags are "installed" with shut off valves. I still need to connect the air lines and torque everything down properly but I wanted to
give it a day or two to make sure they were holding air...they seem to be so far.

While I am waiting I decided to start trying to pinpoint the compressor issue. I pulled the compressor from the coach and connected it to a battery. I
let it run for 2 minutes and it seems to run fine. The compressor was only a little warm on the cooling fins and it was pushing out more air pressure
than I could prevent using my thumb. The connections to the battery I was using started to get quite warm towards the end but I doubt the wires were
12 gauge so I assume that is normal. I didn't want to push my luck and go any longer.

Can I assume the compressor is not the problem at this point?

[Ken Henderson]

Nope. You need to put the compressor under load for much longer than 2
minutes -- using 12+g. wire. Do you perhaps have a portable air tank, or
similar, to which you can connect it? Since you won't be running through a
pressure cutoff switch, monitor the pressure closely so you don't exceed
the rating of the receiving tank. Without that, you need to re-install the
compressor, let all the air out of the bags, provide power directly from
the batteries, and see if it will re-inflate the bags. If not, the
compressor is not up to the job.

Ken H.

On Sat, Mar 11, 2017 at 5:58 PM, Bryan Hartman <bry...@gmail.com> wrote:

> ​...

>
> While I am waiting I decided to start trying to pinpoint the compressor
> issue. I pulled the compressor from the coach and connected it to a
> battery. I
> let it run for 2 minutes and it seems to run fine. The compressor was only
> a little warm on the cooling fins and it was pushing out more air pressure
> than I could prevent using my thumb. The connections to the battery I was
> using started to get quite warm towards the end but I doubt the wires were
> 12 gauge so I assume that is normal. I didn't want to push my luck and go
> any longer.
>
> Can I assume the compressor is not the problem at this point?
> --
>

[Bryan Hartman]

Thank you Ken. I reinstalled the compressor but I did not connect the output back to the tank. It ran for 5 minutes just blowing air through the open
line with no issues. Based on your reply I assume that that still probably wasn't enough of a load. It Once I get the air lines reconnected to the
tank and the bags I will try again.

On a related, when I have the Travel switch on "Hold" and I click "Raise" on either switch the compressor kicks on and blows like I would expect. I
also noticed exactly the same behavior when I put either switch on "Lower" which I would not expect. That is not normal, correct? The compressor
should not come on and blow when the switches are set to "Lower" right?
--
1977 Palm Beach

[Ken Henderson]

Bryan,

The compressor running when Lowering is not LOGICAL, but it's apparently
NORMAL. :-) At least that's the way mine works too. I keep thinking I'll
get a RoundTuit and fix it, but it hasn't happened during the past 19 years.

Ken H.

[Johnny Bridges via Gmclist]

The battery is off mine so I can't check it... but I >think< the compressor doesn't run in Lower. However, there are a bunch of solenoids in the
system, and I can see where if one were to stick or have its wires crossed with another, Lower would bleed off air from the pressure switch and that
would fire off the compressor - whose out put would go overboard along with the bag air.
Look at the setup in the manual, and do a truth table for each position of the switches and figure how to run the air out of the reservoir.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Bruce Hislop]

My '77 Palm Beach also runs the air compressor with either switch in Lower mode. Checking the the wiring diagram and that's how its wired from
factory.
It's never bothered me enough to go any further than check the schematics.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

[Bryan Hartman]

Ok...new info.

I hooked up the compressor to the tank and the right side air line to the completely deflated air bag. I left the left side air line unattached.

When I activate the switch to inflate the right side, everything works as expected and the bag inflates until about 82 psi then it shuts off. I can
immediately switch off the right side, activate the left side inflate switch, and after about a second the compressor fires back up and starts pumping
air out the unattached left hose. I can then immediately switch everything back to inflate the right side and the compressor runs for 10 secs and
shuts off.

??? Bad compressor? Something else?
--
1977 Palm Beach

[Ken Burton]

Ken Henderson wrote on Sat, 11 March 2017 18:59

> Bryan,
>
> The compressor running when Lowering is not LOGICAL, but it's apparently

> NORMAL. :) At least that's the way mine works too. I keep thinking I'll

> get a RoundTuit and fix it, but it hasn't happened during the past 19 years.
>
> Ken H.

I also believe that is normal. I have not looked at the circuit, but mine does the same thing. The compressor should run anytime the pressure in
the tank is low to refill the tank.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Ken Burton]

As long a the compressor is stopping and not blowing the CB, then the on and off of the compressor is determined by the pressure at the air pressure
at the air pressure switch (and tank). It makes no difference if one switch is set low and the other normal (or high), or if both are low, or if both
high.

Compressor off and on is determined by the tank pressure only.

--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Johnny Bridges via Gmclist]

True dat. A stuck solenoid can allow the tank to bleed out the LOWER solenoid settung thereby lowering the tank pressure and causing the compressor
to run when LOWER is selected. A look at the pressure switch with its cover off seems to be in order here. It may simply be pressuring the tank and
turning off as it should.

--johnny
--
76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased

[Bryan Hartman]

Next update (can't wait until I can say "Last Update"):

With you guys' help, I started to think that maybe the system was shutting off the compressor by design. I realized that I still had the coach sitting
really high. When I replaced the bags I used the "6 2x4's" height that Sully recommends in his bag replacement video and I was testing from that. I
was trying to get the system to pick the coach off the 2x4's so I could remove them and then test the lowering. Maybe the height of the coach was
above the maximum allowed pressure?

So I lifted the coach a bit, removed 2 of the boards, and lowered everything 3". I then flipped the "Raise" switch. The compressor ran for just over 2
minutes and raised then coach about 3" before it shut off. I then manually lowered the coach and repeated with the exact same results. (*The "Lower"
switch on that side does not seem to be working yet)

Does that mean the "Raise" is working now and I had just reached the maximum height? Where do I measure to figure out height? Ground to skirt mount
height? Ground to bottom of body molding strip?
--
1977 Palm Beach

[Bryan Hartman]

I think I found it:

http://www.gmcmhphotos.com/photos/misc/p28167-ride-height-maint-manual-page-3a-21.html

So for the rear it should be 11-11/16 from the top of the slot in the frame?

[Ken Henderson]

Bryan,

After 19 years, I still can't say "Last update" with a straight face.

Page 3A-19 of your '77-'78 Maintenace Manual has the diagram of where to
measure and the heights. If you don't yet have that manual, you're
handicapping yourself in your troubleshooting. Download it from bdub.net.

Ken H.

On Sun, Mar 12, 2017 at 1:50 PM, Bryan Hartman <bry...@gmail.com> wrote:

> Next update (can't wait until I can say "Last Update"):

> ​...