96 xj grounding problem

After market radio? Could be in that harness.

[Well I found it. It was the harness that controls the fan speed. For the blower motor in the dash. It was burnt.

It is likely a good idea to find out why it melted down or it may happen again. Pull out the fan resistor pack and look at it. Or for a quick test smell it. It may have been a damaged cable, it may be a component hooked to the cable. You also need to have a look at the fan controls and make sure they didn't meltdown also. And look closely at the connector near the base of the steering column for discoloration and/or melting.

This might be worth your while:

https://www.naxja.org/forum/showthread.php?t=1118073