I just bought a 1990 LX 5.0 Mustang and the fuel gauge is not working. here's the deal: All other gauges work, no fuses blown and the cluster is not the issue. I swapped it with my sons cluster from his 90 lx and same thing happened. Anyone have an idea what a common problem is with these so I can start there?
It very well could be the ground strap to the fuel tank but it could also be the fuel tank sending unit. I’ve had several go bad in my older model Fords. Sending units can be a pain to replace, but it will fix the issue and it is pretty easy to determine if that’s the cause.
Usually it is the grounding strap going to the fuel tank. I’ve had to solder many new wires on mid 80′s to mid 90′s fords.