Ground for rear clearance lights

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randy1

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Jul 5, 2007
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I've determined that the two outermost rear clearance lights have a bad ground, but I think taking down the rear cap headliner may lead to a shattered
piece made of unobtainium. Has anyone come up with a way of re-running a ground wire that doesn't require tearing up the inside? I've thought about
ganging it to an adjacent lights ground or dropping a ground wire straight down until I found a place to connect it. Any better ideas?
--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
 
Randy
Here's a photo of mine. May be of help.

http://www.gmcmhphotos.com/photos/73-painted-desert-230/p42473-gmc-rear-remodel-clearance-lights-005.html

Dennis

> I've determined that the two outermost rear clearance lights have a bad ground, but I think taking down the rear cap headliner may lead to a
> shattered piece made of unobtainium. Has anyone come up with a way of re-running a ground wire that doesn't require tearing up the inside? I've
> thought about ganging it to an adjacent lights ground or dropping a ground wire straight down until I found a place to connect it. Any better ideas?

--
Dennis S
73 Painted Desert 230
Memphis TN Metro
 
One option is to replace those 40 year old mickey mouse leak producers with
modern LED molded one piece lights. They have two wires, one battery
positive, and one ground. They are polarity conscious, which means if you
hook them up backwards, they won't light up. Remove the moly screw anchors
with well nuts, seal it down with 3M 5200 sealant. End of grounding
problems and leaks all at the same time. Just what I have done,
(once-in-a-lifetime ).
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> I've determined that the two outermost rear clearance lights have a bad
> ground, but I think taking down the rear cap headliner may lead to a
> shattered
> piece made of unobtainium. Has anyone come up with a way of re-running a
> ground wire that doesn't require tearing up the inside? I've thought about
> ganging it to an adjacent lights ground or dropping a ground wire straight
> down until I found a place to connect it. Any better ideas?
> --
> Randy
> 1973 26' Painted Desert
> Ahwatukee (Phoenix) AZ
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
There is a harness that runs to all the clearance lights in both the front
and rear caps. There are plugs at each clearance light. Just remove the
adjacent lights to the ones with the problems, and splice to their grounds.
No drama.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> You can usually fish a wire down to tail lights from outer markers.
> Getting wires to the center lights may need inner cap removal.
>
>
> --
> Jon Roche
> 75 palm beach
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
 
On two different coaches, I had to fish a wire from one clearance light to
the other to get my new lights to work; takes all of 5 minutes and a fish
tape and some extra wire. No need to remove the rear cap.
JR Wheeler 78 Royale 73 Painted Desert NC/OR

> There is a harness that runs to all the clearance lights in both the front
> and rear caps. There are plugs at each clearance light. Just remove the
> adjacent lights to the ones with the problems, and splice to their grounds.
> No drama.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>

>
> > You can usually fish a wire down to tail lights from outer markers.
> > Getting wires to the center lights may need inner cap removal.
> >
> >
> > --
> > Jon Roche
> > 75 palm beach
> > St. Cloud, MN
> > http://lqqkatjon.blogspot.com/
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> There is a harness that runs to all the clearance lights in both the front
> and rear caps. There are plugs at each clearance light. Just remove the
> adjacent lights to the ones with the problems, and splice to their grounds.
> No drama.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>

>
> > You can usually fish a wire down to tail lights from outer markers.
> > Getting wires to the center lights may need inner cap removal.
> >
> >
> > --
> > Jon Roche
> > 75 palm beach
> > St. Cloud, MN
> > http://lqqkatjon.blogspot.com/
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

I'd rather not remove the rear cap headliner if I can avoid it.
--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
 
You don't have to. All access is from outside the coach.
Jim Hupy

> > There is a harness that runs to all the clearance lights in both the
> front
> > and rear caps. There are plugs at each clearance light. Just remove the
> > adjacent lights to the ones with the problems, and splice to their
> grounds.
> > No drama.
> > Jim Hupy
> > Salem, Or
> > 78 GMC ROYALE 403
> >

> >
> > > You can usually fish a wire down to tail lights from outer markers.
> > > Getting wires to the center lights may need inner cap removal.
> > >
> > >
> > > --
> > > Jon Roche
> > > 75 palm beach
> > > St. Cloud, MN
> > > http://lqqkatjon.blogspot.com/
> > >
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> I'd rather not remove the rear cap headliner if I can avoid it.
> --
> Randy
> 1973 26' Painted Desert
> Ahwatukee (Phoenix) AZ
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Are the clearance lights supposed to be 7 volts? That's all the voltage I got.
--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
 
So the adjacent light ground trick didn't really work due to a poor ground there too. The bulbs are much brighter with 12v going through them! I'll
have to find a decent ground somewhere.

Jim, how did you ground from outside the vehicle?
--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
 
No place on plastic. If you are working on the front end, remove the
speaker/courtesy light grill, and probe for ground on that harness. In the
back, there is a master ground near the driver's side tail/stop/back up
light assembly that you MIGHT be able to fish to, by removing the light
assembly. What I would try. Might be a ground in the rear speaker grill if
it is an early coach. That is a bit closer to the rear clearance lights.
Jim Hupy

> So the adjacent light ground trick didn't really work due to a poor ground
> there too. The bulbs are much brighter with 12v going through them! I'll
> have to find a decent ground somewhere.
>
> Jim, how did you ground from outside the vehicle?
> --
> Randy
> 1973 26' Painted Desert
> Ahwatukee (Phoenix) AZ
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> No place on plastic. If you are working on the front end, remove the
> speaker/courtesy light grill, and probe for ground on that harness. In the
> back, there is a master ground near the driver's side tail/stop/back up
> light assembly that you MIGHT be able to fish to, by removing the light
> assembly. What I would try. Might be a ground in the rear speaker grill if
> it is an early coach. That is a bit closer to the rear clearance lights.
> Jim Hupy
>

>
> > So the adjacent light ground trick didn't really work due to a poor ground
> > there too. The bulbs are much brighter with 12v going through them! I'll
> > have to find a decent ground somewhere.
> >
> > Jim, how did you ground from outside the vehicle?
> > --
> > Randy
> > 1973 26' Painted Desert
> > Ahwatukee (Phoenix) AZ
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
> Yeah, removing the rear light might make it much easier. Thanks!
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
 
I believe, though I have never actually traced it my self, that the ground for the tail lights, brake lights, and back up lights, ALL share the same
common ground with the clearance lights that leads back to the engine ground system.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
> You should be able to ground to anything metal, fish a wire down or even ground it to the body somewhere.

I caution you not to do this. Unlike a normal auto or truck there are three separate ground systems on a GMC coach. Under the right failure
conditions you could end up pulling a high current across the ground wires going to the rear lights and burning them inside the wiring harness.

If you need a more detailed explanation of this I'll look up the GMC grounding presentation on the GMC Eastern States site and refer you to it.

If you are going to run a new ground wire, or wires, they need to go to something grounded on the engine power system and NOT to the house body or the
steel frame.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
After much fishing of coat hangar and wire, I was finally able to piggy back the outboard clearance light ground to an adjacent light ground. Now,
onto the other side. In the morning though, when it cools off. 😀
--
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
 
> One option is to replace those 40 year old mickey mouse leak producers with modern LED molded one piece lights


Hi Jim, do you have a preferred make/model of molded light that has a similar footprint to the OEM lights?
Thanks,
Jim
--
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH
 
I believe I have seen the exact same shape (teardrop)light with LEDs in the NAPA store,available in red and yellow. I think they are made by
Grote...if I get by there today and the name is different I'll correct this posting.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Both Jim's have them.
--
Christopher Brewer
Chattanooga Tn
1975 Palm Beach
Still mostly original
EV-6010 Norcold 962 Sully's Wireless Air Mach 15k
Gettin better, $1 at a time...
 
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