The switch itself works because the little light turns on and it turns itself off after the right amount of time, the rear window just doesn't defrost.

The rear dome light also doesn't turn on when I open the hatch but it will turn on if turn it on manually by pressing it. I'm wondering if there is a break in the wire somewhere?

Anybody else ever experience this problem??

Pictures of my last XJ for views:

 

Take a voltmeter and check to see if you have power going to the defrost strip. Check continuity across the strip.
Also depending on the way the switch is wired internally it could be bad on the output side and the light still work.

 

i have the same problem!!! but when i manually turn on the trunk lights they come on dim and the plate lights and brake lights come on??