Fuel gauge issue

So a wiring issue? How do I check for continuity? Any ideas? Thank you

Yes but a wiring schematic is really needed to trace the circuit up to the IP so continuity can be test at both ends. I would start by looking closely at the connection behind the instrument panel that feeds the printed circuit... Hard to help much over this d--n internet!.. Maybe try YouTube for a video.. Ya never know!

We bought the car used with 180,000 miles just about a year ago. Your shop replaced the air/fuel sensor when we first got it because of a check engine code and it has been running fine. It already had an aftermarket radio and alarm on it when we got it and the gas gauge worked fine for about 8 months. Mileage is now about 190,000. The gauge has gone down to about 1/2 tank recently but just a few times with the new cluster in it. I was told that if disconnected, the gauge should go to empty with the key turned on but it won't go below about 3/4 as of yesterday (it actually didn't move at all but has in the past from full to 3/4 but it was already at the 3/4 mark yesterday).

It is possible for an aftermarket part to fail or the connection to the vehicle to cause problems. If they were not careful how they routed the wires for instance. If they tapped into a wire that feeds the cluster and that aftermarket wire had been rubbing against a piece of metal for years it may have finally rubbed through and coused the cluted to get a ground it was not supposed to get, for example. If you need help we are here. Thanks

Okay, thanks. Still deciding to proceed and have it fixed or live with it. I'll be in touch.

Good Luck