I have a 72 chevelle gas gauge worked properly when I purchased it sometime after filling it up I noticed the gauge went all the way to
3:00 and has stayed. I unpluged it at the rear of the car and put 12volts
to it ; it moved to 4:00 when took off voltage it returned to 3:00.
Please help.

Ground the sending unit wire it should go to empty, then leaving it open it should go over the full mark. This test checks the gauge in the dash.

Dave

Did what you said. Gauge went to E when I disconected it went back to 3:00 whats next?

around 1:00 would be full

Double check the ground wire. I believe it is just sheetmetal screwed to underbody in front of tank. take it off clean area it attaches to and clean ring at end of wire & reconnect. The gauge on my ElCamino acted up & this fixed it.

thanks for your help I will try that and see if it takes care of the problem. I am a little sceptical since it went way past full without reconnect the sending unit

Did what you said. Gauge went to E when I disconected it went back to 3:00 whats next?

What's next?? How about some punctuation marks so we can understand what you said?? :confused:

Here is what should happen. Disconnect the sender at the connector behind the license plate or where ever it is easy for you to get to. The Tan wire is what you're looking for. Take the wire, and ground it to the body. Your gauge should go to "E". If it goes back to 3:00 when you reconnect it, you have one of two problems. Either the ground for the sender is bad as mentioned above, or the sender in the tank has opened up the circuit. :thumbsup:

would that be the same for a 66 my gauge is stuck on full. I unplugged wire of back of tank and nothing happened

same thing on my 70

I have the same problem, please keep me in the loop if you get it repaired. jstewart@nelbran.com
Thanks, Joel

Here is what should happen. Disconnect the sender at the connector behind the license plate or where ever it is easy for you to get to. The Tan wire is what you're looking for. Take the wire, and ground it to the body. Your gauge should go to "E". If it goes back to 3:00 when you reconnect it, you have one of two problems. Either the ground for the sender is bad as mentioned above, or the sender in the tank has opened up the circuit. :thumbsup:

Here's how to test it, go out to the garage and get to work! :thumbsup:

Mine did the same thing, after testing everything I replaced the sending unit. Works perfect now.
Ron

I had the same problem......
I took out the sender & cleaned the 'lock ring' that holds the sender in (it had a tiny bit of rust on it) & it works fine now