Any one know why the a/c compressor kicks on when the heat is turned on. Just got my sons XJ running and when you turn on the heat on high the compressor clutch kicks in and the thing squeals like crazy. same with a/c on, but that causing the clutch to kick in I understand.

Compressor bad?

The compressor should only kick on with the A/C or Defrost on not regular heat.

If you don’t want the AC, they make a pulley to eliminate the compressor. I did that in my XJ. I had nothing but problems with my AC, not to mention your mileage and power decrease quite a bit with it on.

So if it comes on when in the defrost position that is normal?
Is the compressor bearing servicable?