Chrysler Repair: 1999 Concorde 3.2L Gas Gauge Bounce, fuel level sensor, alldata online

Question
Hi Ron My gas gauge bounces up and down periodically the low gas light will come on and the Chime will go off each time the needle is on empty. Any Idea on the fix or how to disable the chime noise. I have the ALLDATA online manuel for this car also saw this problem listed on other web site with no solution posted.  Thanks Barry

Answer
Hi Barry,
My suspicion is that the float or the variable resistor of the fuel level sensor in the tank is faulty, because that is the mechanically variable part of the system, the rest is hard-wired or solid state. The level and the warning chime are mediated thru the body computer: it looks at the resistance of the tank unit and puts out a digital signal to the cluster and a signal to the chime if it sees a resistance that is too high (which is consistent with the variable resistance having an "open" discontinuity along its path (such as the moving sweeper loosing contact with the surface of the resistor which would cause an infinite resistance=empty). When that occurs the body computer sends a digital signal that drops the gauge and sounds the chime.
There is no way to stop the chime unless you disable the chime which of course will cause all alerts of that type to be silenced as well. My theory could be verified by monitoring the resistance to ground of the wire from the sensor where it comes into the body computer. Unfortunately my most recent manual is a '94 which shows the body computer to be located on the right side of the passenger compartment, under the dash, just in front of the passenger door opening, behind a panel/carpeting with an underlying cloth covering that you would cut to gain access to the computer. By '99 it might have been moved to the left side underdash, in which case it would be packaged together with the junction block (fuse box). So you would want to take a look for the computer to see if it is behind the fuse box or still over on the right side.
The computer had 3 plugs in '94 and the specific wire color is probably unchanged (dark blue) and was found on pin 23 of the gray-colored plug. If you verified that the resistance was in fact jumping in synchrony with the gauge/chime that would allow you to move ahead to change sensor as the solution. The sensor and fuel pump are a single unit, but once removed from the tank the sensor can be separated and replaced alone. The access if via a covered hole under the floor mat in the trunk (fortunately the tank does not have to be 'dropped' as in other models). I can send you the pages on doing that changeout once you conclude that is indeed the reason for the problem.
There is always the possibility of a break in the wire from the sensor to the computer or a faulty connection in the plug at either end so you would want to wiggle the wire while checking for continuity between each end of the wire (computer-tank sensor).
So that is how I suspect the problem occurs and its remediation.