Chrysler Repair: 1992 chrysler fifth ave. fuel gauge always full, chrysler fifth ave, chrysler new yorker

Question
i have a 1992 chrysler new yorker fifth ave and the fuel gauge (digital) is always pegged at full.all the other gauges work fine.is there something i can do to fix this? thank you

Answer
Hi Robert,
The chances are that the fuel sender unit (the smaller unit of the two found at the tank) in the tank is faulty or its signal wire is grounded as that is what will cause the gauge to read full.
The wire that carries that signal is dark blue/yellow in color and would be found at the top of the fuel tank, toward the rear of the tank. It goes to the body computer at its black plug, pin 18. I would suggest that you check that wire after disconnecting it at the body computer to see if it reads 0 ohms to ground or not, then unplug it  at the fuel tank and read it again, and finally check the resistance at the pin on the fuel tank sender itself to which the wire is attached to determine exactly where the grounding problem is located.
There is also a self-test of electronic cluster. Basically you simultaneously push the trip and trip reset buttons and start the engine, then release the buttons.  "chec" should appear in the odometer window.  Then press the us/met button and release it and watch the odometer to see what you get.  A 999 is fine, otherwise let me know. After that point if the gauge reads full and the cluster asterik is not flashing then do a measurement of the resistance to ground at the cluster pin 18. Normal reading would be 2 to 150 ohms. A reading below 2 or over 150 would verify a wiring or sending unit problem. There are other aspects of the test but this is the subtest for a fuel gauge problem.
Roland
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