Fuel Gauge stopped working, was reading incorrectly before that...

[reluctant_owner]

My partner purchased a Rialta against my recommendations and it has been nothing but problems since she got it. After replacing the cabin batteries, engine battery, fuel pump, fuel pressure regulator, fuel filter, mass-air flow sensor, catalytic converter, and O2 sensor the thing actually worked pretty well. For a while...



The lastest issue is the fuel gauge just stopped working all together. When we replaced the fuel pump we thought that the reason the gauge wasn't working properly was that the sender was oriented in the wrong direction. During replacement we made sure that it was oriented as indicated in the service manual but that didn't fix the issue (refused to show more than 1/2 tank when full). Now, we don't get an indication from the gauge.



Steps I have taken to trouble-shoot:


1) I verified that the sender is still providing variable resistance by measuring the resistance on the two center pins and moving the arm on the sender. Checks out between 55 and 95 ohms.


2) I looked in the service manual and it appears that the gauge is directly connected to the center pins and their should be 12 volts of voltage across them when the engine is on. Measured it and am getting no voltage at all.


3) Tried using a spare 12 volt battery to provide voltage on the two center pins and this also did not make the gauge move at all.



At this point I am thinking that the wires from the fuel pump assembly to the guage must be bad some place. Anyone got an idea what to do next to test and correct this issue? How hard is it to trace these wires and get to the back of the gauges? I couldn't see an easy way to get back there or to remove the gauge cluster.



Thanks in advance!