Impalas.net banner

1 - 6 of 6 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter #1
Hi....My fuel gauge has stopped working.....
I have power at the cluster, have power on the third terminal on the cluster plug
I have power/good ground at fuel tank
I just replaced the circuit board in the dash cluster...
How do I check the gauge to see if it's working??? 3 terminals on the back of gauge, can I check it from there?

Thanks in advance
 

·
Super Moderator
Joined
·
13,041 Posts
Problem is usually associated with a bad ground. Taking everything apart and reassembling it usually fixes the bad ground. Since you have done that (dropped the tank and removed the wires to check electrical continuity) then it will be a mater of checking every inch of wire for an open circuit.

Big dave
 

·
Registered
Joined
·
24 Posts
Discussion Starter #4
Am I missing something... I have power AT the gauge and sender. HOW do you check the gauge to see if it's working.. Three terminals on the back of it, can it be checked there for problems?
 

·
Super Moderator
Joined
·
13,041 Posts
The gas gauge is a volt meter. It tells you the amount of gas by dropping 12 Volts through a 90 Ohm resistor to ground. If you had a varister (rheostat) you could test the gauge and even calibrate it to match your car's circuit resistance. It is rarely ever broken, as the problem is much more frequently found at the other end of the circuit. But if you guess wrong while testing it and you will let the sacred smoke out and have to replace it. For instruction on testing it look to the service manual for your car year.

If the gas tank sending unit doesn't have a good ground it will never work. The sender is grounded to the bottom of the trunk floor by a short wire coming out of the top of the sending unit which you can not even see until you drop the tank. It is exposed to the elements, road salts and collects debris on the top of the tank (it is frequently also the location of a build sheet) so there is often a lot of corrosion which changes the resistance of wire terminals.

Big Dave
 

·
Registered
Joined
·
24 Posts
Discussion Starter #6
So Dave.... Can I test the gauge "simply" some way from the three terminals on the back of it?

The gas gauge HAS a good ground!!! The sender is easily removed from the tank without dropping the tank, 2 minute job. I have good ground at the tank and have power at the tank. ( only EVER seen a build sheet on a Corvette on the tank) Metal was bare at the ground when I checked it.....
 
1 - 6 of 6 Posts
Top