Jaguar Repair: 86 xjs speedometer gas guage, gauge needle, fuel gauge

Question
86 XJS speedometer, and gas guage are dead.  Tach works fine

Answer
Hi Andy,
If the tach is working then the fuse powering the fuel gauge and speedo is working.
Check the trip computer and the cruise control, if they do not work you need to check the pulse generator on the transmission.

None of this has any connection with the fuel gauge. So you need to test it also. Remove the Light Green w/Orange tracer wire from the sending unit and watch the gauge (key on) Then scratch the wire across a ground and note the gauge. The needle should swing full over in one direction open and scratched on a ground it should go the other direction. I don't remember which way on each but that does not matter as long as the gauge needle moves all the way. The third wire is just a "Low Fuel" indicator and it can be tested by grounding the Brown w/pink tracer wire at the sending unit. Be sure the Black wire is a good ground at the sending unit.
Howard