[daves57]

hope you can help, when i turn my lights on the gas gauge goes to empty, if i turn down the brightness of the dash lights the gas gauge goes back to normal, would like to figure this out without going to electrical shop thanks good luck dave.

[george kujanski]

Poor dash ground to firewall/battery negative connection or corrosion/loose connection in the battery feed wire that comes thru the firewall bulkhead connector.

George

[Peter Serio]

Hi, what year make and/or model car are you working on?

["QUICK-SILVER"]

I'll say definitely a weak/bad/poor ground to the gas guage or instrument cluster.

Adding a ground wire at the back of the instrument cluster to something solid under the dash should fix it right up. Especially in the area of the gas guage if it's in a seperate pod, the whole cluster if not.

The light current is just plain stronger than the current that moves the gas hand. Dimming the lights equalizes the currents letting the gas hand come back.
A good ground will stop the arm westling match. Each will get it's on fair share of ground.

Repairing the OE ground would actually be MY first choice but could be quite a bit more difficult.

[daves57]

thanks for the help, its on a 69 bird, ill check all grounds and add one if need be.i think i inhereted an electrical nightmare here. although most things work fine someone has plugged wires into the fuseblock, just stuck them at the ends of the fuses and i dont know what they control. my neutral safety/ backup light switch combo. does'nt work i noticed one side has a plug going to it and the other side does'nt and i cant find a 3 prong plug under there to plug it in. oh boy here we go thanks dave