JPMDaddy

My new 71 Cutlass Supreme convertible only has idiot lights and a fuel gauge that isn't working.

I'd like to get gauge working/replaced or better yet, upgraded with full gauges.

507OLDS

I have some spare fuel guages,with the lights,but no spare rally guages with the needles.

ROCKETMAN269V

You may have an electrical problem with your fuel gauge. It's easy to check. In the trunk is a tan wire with a black spade connector, near the trunk latch. Unplug the connector, turn the key on and see if the gauge is "pegged" passed it's normal range. Now ground the side of the connector that goes forward to the dash and see if it "pegs" the opposite way. If it does, your dash gauge is fine and you need to check your gas tank sending unit. Grounding the wire will not damage anything in your gauge circuit.

JPMDaddy

@ROCKETMAN269V thanks for troubleshooting tip... I know that a lot of the El Caminos are troubled by ground issues too. Right now the needle is somewhere over the HOT light.

I will check that out first, but I want gauges not idiot lights.... I've seen a couple of 4 in 1 gauges that might look good and fit.... I'd like to keep the car fairly original.

Tony72Cutlass'S'

So for what it’s worth, it took me 8 years, but I finally bought a new fuel tank.

and the saga continues! Stay tuned another 8 years for me to post some pictures

jollyolds

they repop the rally pac gauges and wiring-parts place is one source

Cutlassfarmer

I have a very similar problem with my 70 Cutlass Supreme convertible. Can I check the same wires in the trunk too?
My problem with fuel gauge started when the pump at gas station did not shut off and I over filled gas tank. Gas gauge went way to right almost to 3 o’clock position. I have been driving car and now gauge is showing just below full but does not seem to want to go lower. I have been driving it enough that the fuel level should be going down.

My thought is to run the test with grounding the brown wire. If that seems ok it must be sending unit in tank?

Is this the way to debug this fuel gauge issue?

ROCKETMAN269V

Same procedure as I mentioned above.