Gas gauge effected by light switch

[JimmyC]

My gas gauge was not working so I started tracing it down. I found the power lead was disconnected at the gauge, hooked it up and everything was fine until I turned the lights on. When I did that the gauge pegged on the full end. Fiddled with it a bit and could not make any sense of it. Will look at it again tomorrow and will have my meter this time. Any suggestions?

[Pinz710m2]

The connector for the wire that goes to your
left brake light is the same connector that
controls your gas gauge. There might be a
broken connector or frayed wire there. A
great color wiring diagram was just posted on
here.

[undysworld]

Manually grounding the wire that runs from the meter to the sender will peg the meter. The gas sender unit has its' lowest resistance when the tank is full and gives you the highest reading on the meter. The resistance increases as the tank gets emptied, thus the lower reading on the meter. I'd be guessing you have an issue with the ground from the meter.

Since the gas gauge reads normally with the lights off, I'd suspect it's somehow grounding out through that circuit.

[JimmyC]

It turned out the wire grounding the gauge itself was bad. I ran a better ground to it and everything is hunky dory