No Fuel Indication

I'm quite the lurker; I've been reading on this forum for a long time, but never posted. Here's my history. I'm swapping all the guts from a '97 XJ (4.0) into my '90 MJ. After swapping everything I can get the truck to run, but I don't have a working gas gauge. It reads empty without the low fuel light coming on.

Is there a separate ground for the sender that I may have missed?

In the infinite wisdom of Chryco the gauge reading resistance values were reversed.

Be more specific on "all the guts" re: tank, sending unit, instrument panel, wiring harness.

joe_peters said:

In the infinite wisdom of Chryco the gauge reading resistance values were reversed.

Be more specific on "all the guts" re: tank, sending unit, instrument panel, wiring harness.

Click to expand...

Everything is the same except the tank. I used an adapter ring on the MJ tank to accept the XJ pump assembly. Other than the bed, its a '97 XJ.