OK, so when I turn my lights on my fuel gauge (i've got the V6 cluster with idiot lights if it makes a difference) goes as far below "E" as it can. But if I turn the dimmer switch and turn the panel lights off the gauge starts working again. I've been having other problems with this cluster too. The left blinker indicator occasionally stops working, and the temp idiot light never comes on (the bulb is good). I took the cluster out and cleaned the contacts where it plugs into the dash, hasn't helped. Any ideas? This is in my camaro btw.
Thanks guys
Alex

 

I have a similar issue. When I turn on the headlights, the fuel gauge goes to below empty.
I have an original V6 Camaro, chassis and dash with a new tank and used sending unit from an earlier carbed vehicle.
I haven't sourced out the cause of the problem yet however I'm reasonably sure it's in the ground part of the circuit. It's just too cold here to go into the garage.
I'll be interested to see if anyone posts a solution.

 

normally that happens when the cluster is loose...try pushing on the cluster to see if it makes a difference

 

Interesting. I'll be swapping the cluster for what's in my old IROC. Maybe that'll be the fix.
Thanks.

 

Just went out and tried that. If I push as hard as I can it starts working. Thanks for the help. However, the nuts securing the cluster are as tight as I can get them, think I need a new cluster?

 

even though you cleaned the contacts it still may be loose fitting, check the contacts between the harness and the cluster, dont try overtighting, it probally wont help,its the illumination wire and grnd that cause this prob.im trying to remember what i did to fix it..

 

Thanks for the help guys, I've got a hunch on what it is. I'll post again tmrw if I'm right.