Fuel gauge hasn't worked properly in years. Had cluster checked by Hamp'* Speedometer Repair in Atlanta (nice folks!) and it checked out good. Wiring between fuel pump and cluster checked out. Replaced sending unit with a Dorman with no improvement. In tracking down things to test, one item is to disconnect the fuel sender assembly and install a jumper between the fuel level signal and the fuel level ground circuit in the connector plug. Presumably, the black wire is the ground, which of the other wire is fuel level signal wire?



01 Park Ave fuel sender assembly connector

Are you sure the level harness goes straight to the cluster? 96 and newer, the ECU gets the signal first, then the cluster. This is so the ECU knows when to do EVAP tests.

I don't know.... Working on this without the benefit of a shop manual, so I don't have any schematics.

A couple of the other things I did was to check wiring continuity and resistance between the fuel pump and cluster. Continuity good, ohms 0.

Another exercise was to stick a resistor of a certain value in the connector plug and check resistance at the cluster plug. Three different resistors will give approximate gauge reading (3/4, 1/2, etc.). All three resistors produced the expected readings on a VOM.

I dug around and found the original sending unit that I replaced a few years back. I figured that the solid black and purple wires connect to the sending unit and put a jumper across those terminals and turned key to on. Fuel gauge reads empty, so does that indicate that the sending unit is where the problem is?

Below is the original sending unit. The rheostat consists of two wipers that have three "fingers" that contact the tracks. Two of the three fingers on the upper wiper are missing and the lower wiper fingers appear to be rusted and are curled up. Not surprising that the fuel gauge stayed on full all of the time


Original? sending unit

Sending unit is suspect. Ground the input and full open should produce empty and full.

Those fingers that come in contact with the board are worn out badly. Probably don't even make contact anymore. Time for a new one. Just replace the whole unit with AC Delco.

Jumped the two leads (purple and black) in the fuel sender assembly connector and the fuel gauge in the cluster reads empty. When everything is connected the dash fuel gauge may read 1/2 one minute and full the next.

Looked up past orders on Rock Auto and I ordered a replacement Dorman sending unit on July 9, 2017. It has worked no better than the original sending unit pictured above.

The photo is actually the ORIGINAL sending unit I removed in July 2017. I replaced that one with a Dorman and have three more years of an erratic gas gauge. The next one will be an AC Delco. This seems to be a common problem with Park Avenues