# Grounding dash lights, bulbs in wrong sockets?



## pbertrand65GTO (Jul 24, 2009)

I am able to ground the back of the clusters, but I got two clusters to light up,
then when I grounded the next one, one of the clusters that were lit shut off.
The only conclusion I have is that the bulbs may be in the wrong sockets?
I'm using different grounding points that I know are good grounds.
Has anyone had this happen, or am I the only lucky one? I'm losing what's left of my mind.
Any ideas would be appreciated.


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## rickm (Feb 8, 2012)

its been a while since I was under the dash, but isn't there 1 main ground location for the dash circuts? the dash wiring diagram will tell you by wire color what bulb socket goes where. lighting sockets wires are all grey if I remember.


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## jbrenner (Apr 15, 2013)

Interesting. I restored a 66 and installed an aftermarket wiring harness. I ended up feeding many of the dash grounds to a large bolt I installed through and existing hole in the frame under the dash near the steering column. Just made sure all the paint had been removed so as to ground direct to metal. Obviously the bulb sockets themselves ground in the dash gauge housing they plug into. It's possible you have a few sockets with some buildup on them or that the socket holes themselves have some buildup on them. I'd take a piece of heavy grit sandpaper to both and make sure the contact spots are clean. You could also have a grounding issue elsewhere that is showing up as you plug the bulbs in. If so, this problem has a tendency to show up in the oddest of places. Make sure the battery has good ground to the block, the inner fender well has good ground to the frame and the rear of the engine block has good ground to the firewall. Again all spots having been cleaned of paint and other debris so that there is solid metal to metal contact. I had to run a separate ground wire to the passenger side rear tail light as well because it was dimmer than the driver side light. Once good ground achieved the problem is corrected. In a nutshell you can't have enough good ground.


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## 68_Goat (Nov 7, 2008)

Had a 69 GTO, and it had a poor ground connection to the gauge cluster. Would hit the brakes, turn signals, and dash lights would get bright. Ran a new shunt to a known good ground location, and problem was solved.


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## pbertrand65GTO (Jul 24, 2009)

*Thank you*

Seeing as how I don't have the inner fenders reinstalled, and I haven't checked the battery ground, I guess I know where to start. I will do that first, double check the other grounds, and go from there.
Thanks guys, very much appreciated!


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## pbertrand65GTO (Jul 24, 2009)

It worked! JBrenner, I put a bolt in that threaded hole in the frame, sanded the battery ground connection to the block and viola! The only thing left under there is the directional and high beam lights. I need a few new bulbs, but I'm not sure if those sockets take the longer bulbs with the plastic housings.
Thanks everyone, for your help, great way to end the night!


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