C1 Gas Gauge Peg at Full Update

[Bob B.]

Hi all,

I previously wrote a question about my gas gauge pegging at F out with the ignition on. Since then, I have removed both wires to the sending unit and even the sending unit wire from the gauge. All that is left is the pink wire, and the gas gauge still pegs when I turn the ignition on. If I switch terminals, it pegs at E. It seems that the gas gauge shouldn't do anything unless both wires are attached, so how is a circuit being made with only one wire? As mentioned, the gas gauge was rebuilt and even checked by a third party prior to installation, but maybe something was missed?

I traced the pink wire and unhooked it from the temp gauge. It also goes to the fuse block, so I took the fuses out that connect to that wire. I took the fuse block off and checked the back and all was fine.

Any ideas on this from the update?

Thanks,

Bob

[Joe C.]

Re: C1 Gas Gauge Peg at Full Update

Bob,

The cluster housing is grounded. At the upper middle cover attaching screw, you should find a lug. This should be connected to chassis ground.

Joe

[John H.]

Re: C1 Gas Gauge Peg at Full Update

Bob -

Assuming the gauge housing is grounded (through the cluster), if the sending unit wire is disconnected (either at the sending unit or at the gauge), the gauge should peg to "Full" when you turn the key on; if you ground the sending unit wire (or the gauge terminal), the gauge should peg to "Empty" when you turn the key on. That will verify that the gauge is responding properly.

Don't connect the pink (power) wire to the gauge "S" (sender) terminal - that will fry the gauge.

With a VOM (set to ohms) across the sender wire terminal and ground on the sending unit flange, it should read zero ohms with the float all the way down (empty), and 30-33 ohms with the float all the way up (full); that will verify proper sending unit function.