The Stovebolt Site Forums The Shop Area The Electrical Bay gas gage mystery

have new 12 v gage. new sending unit. getting 0-40 ohms on sending unit when i move the arm. getting (minus 10-12v) on back of gage when key turned on.
tank is about 3/4 full and i can get about 25 ohm reading on sending unit.

gage goes to Empty when key turned on.
tried new wire from gage to sending unit-same response. is my problem that i am getting a minus voltage reading?? this is a 12 volt conversion with negative ground. could the sending unit be shorted out?? help

after couple more hours and trip to auto store. i discovered that i needed to ground the gage. i had it out of the cluster justing hanging. once i grounded the gage the needle pointed to 3/4 full.

doug

I am having the same problem. I installed the new 12v. guage into the cluster and now I am getting about 6v. at the sender. If I remember right there should be no voltage at the tank. I also have a new sender in the tank but have not hooked it up yet. I am getting all of my readings at the wire at the tank. Don't want to burn up the sender. Anyone have any ideas whats going on?

It is my understanding the the sending unit can be used with either 6 or 12 volt systems. That is what I was told when I bought mine. I have 12 volts and the sender works fine.

Test your sender by taking it out of the tank, then using a multimeter on the Ohms setting, place one lead on the top stud of the the sender and the other lead to the plate of the sender (ground). Then, move the sender arm up and down. It should register 0 ohms with the arm all the way down (empty), and 30 ohms with the arm all the way up (full). If so, the sender is good, and the problem lies in the gauge or connections. Note: these Ohms readings are for the pre-1965 GM vehicles, but the testing procedure is the same for others as well.

Hope this helps,
Steve