Right rear turn signal issue

[shawn bennear]

I have been out tinkering with the Palm Beach and I am going to be going after the issue of no right rear turn signal. I feel pretty sure the turn
signal switch in the column is OK, as the front right signal is working. I am thinking that somewhere there is a break in the wiring between the front
and the rear of the coach. I am also planning on changing out the tails to LED.

I'd like to test the wires back there with my handy test light. I am not sure where to ground the test light out at. I am not sure if it will ground
to the aluminium frame of the coach. I really need to get this fixed and I'm hoping I don't have to run a new wire. I'm still trying to figure out how
to even access the right side taillight from inside...

Apparently, the PO must have thought it was easier to run a power wire along the frame and up through somehow. I don't like to jury rig anything, so I
plan on doing this correctly.

Any thoughts would be greatly appreciated!
--
http://www.gmcmotorhomeworld.com

1977 Palm Beach, 403 V8 w headers.

 

[Melbo]

When I am checking a circuit I ALWAYS connect a ground directly to the battery negative terminal and THEN and ONLY THEN check for power at whatever it
is I am checking. That way I know that I have a good ground and I am really checking if there is power at whatever I am checking.

HTH

Melbo
--
Albuquerque NM Bus Conversion 1978 MCI 1973 GMC

 

[RF_Burns]

The rear turn signals share wiring and lamps with the stop light and 4-way Hazard functions, so I assume those functions do not work on the right side
as well. If the Stop light and 4-way Hazards work but the right turn signal does not, I would suspect the turn-signal switch.

Turn the parking lights ON and check that they are operational on the rear. Then turn ON the right turn signal... if the right rear goes OFF (parking
lamp on the right goes out too) then you likely have a bad socket ground between the socket and the lamp. In this case, turn off the parking lamps and
turn signal, clean the socket and lamp shell, then try it again.

Checking for power at the rear light signal is a simple task. Remove the lens and check the lamp, it may be just a burnt out bulb. Turn on the parking
lamps and clip your test light ground clip to the frame. Getting a good ground is likely to be the tricky part which is why I said to turn on the
parking lamps. The light socket has 2 contacts, one for Stop/turn/hazard and the other for the parking lamps. You should have power on at least one
contact otherwise you likely don't have a good ground for your test light.. try cleaning the rust and or paint under the ground clip and try again.

You should be able to get power on both contacts, if so suspect the lamp is faulty. If you get power on one contact and not the other, then the one
with power will be your parking lamp and the other is your stop lamp. Troubleshooting the wiring will require the chassis wiring diagram (download)
and some work to find it the problem.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.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

 

[richard h staples]

Shawn,
Yes, you should be able to ground your test light to the aluminum body structure unless there's a bad ground to the body up front from body to frame.
(unlikely).
First question: Does the right rear stoplight work? Since this is the same filament as the turn signal, if it does, then the problem is almost
certainly in the turn signal switch. Assuming it does not, then some tracing is in order.
According to the wiring diagram, the right stop/turn wire is dark green 18ga. I would first check for power right at the bulbholder. Corroded
terminals or rusted contact springs can cause much grief. Assuming you do NOT have power on that circuit at the lamp, I would go to the 11 pin
connector down on the steering column, again checking the dark green 18ga wire.
If you DON'T have power there, the turn signal switch is again suspect. If you DO, then the problem lies in the wiring from front to rear. According
to the schematic, there is a 10 pin connector in the upper left of the dash, and a 6 pin connector in the left rear "carling", whatever THAT is.
(Thanks GM for the typo or just plain obfuscation!) According to the schematic, the circuit is all dark green 18ga all the way from the turn signal
switch to the right rear lamp assembly, which should simplify tracing it.
I must admit I'm doing this solely from the schematic, and your coach may have been modified, but this should get you started.
HTH
Rick Staples
--
Rick Staples, '75 Eleganza, Johnstown, CO

"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien

 

[SteveW]

After replacing the rear tail lights with LEDs - it's quite likely that all of your blinkers will blink faster than they used to...

Happened to me - and they were blinking so fast that is was difficult to notice any distinction between the parking light and the blinker light.

A replacement flasher from Amazon fixed the issue.

https://www.amazon.com/gp/product/B00JXLH7CG/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

Hope this helps.
--
Steve W
1973 : 23'
Southern California

 

[shawn bennear]

Thanks everyone for the info. I did find a few issues in the drivers side rear section, corrected those, still no dice. I did find something
interesting though.

When I was changing out the old style tail lights to install the ones I got off of John Wright at the Mansfield rally. I found on the right side that
it appears the ground wires are simply hooked to the aluminum housing that the light sockets are on. I wouldn't think that would be a good ground at
all, unless I'm missing something...And I may be...

The PO had a wire (or 2) running from the dash down to the frame, then under every hole in the frame they could find. just hanging there... I don't
like that kind of a repair. I want to do it the right way.

Just not sure about that ground connection on that aluminum taillight housing...

Shawn

PS, The old backup light had just one wire, the new one has 2. Would I be OK to hook that ground on the reverse light to the 2 other grounds I
mentioned?
--
http://www.gmcmotorhomeworld.com

1977 Palm Beach, 403 V8 w headers.

 

[shawn bennear]

Just wanted to let you all know the problem has been fixed. I used those grounds and connected the new lights to them, then I went looking under the
steering column, and I found the PO, for some unknown reason, cut the dark green wire for the passenger side turn signal and had it hooked to a red
wire which ran along the coach frame to the rear. Why?? I have no idea... I removed all that, and hooked the wire up correctly, and all of a sudden I
have the pass side turn and brake light working... Thankfully...

Thanks for all the advice, as always, its appreciated!

Shawn
--
http://www.gmcmotorhomeworld.com

1977 Palm Beach, 403 V8 w headers.