rear defrost

i have an 88 4.0 AW4 and the rear defrost isn't working. i replaced the switch with one from a junk yard with no luck. it seems that all the visible wiring on the window is in tact. Is there a relay that may be bad that i can change? if so where would it be?

thanks

I've got a 99 with the same symtom, I've got evedance of some wire harness wear going from the headliner to the rear hatch. If you check there, my guess is you've got a short in that harness.

put a meter to the wires on the window see if you have power there i wasnt sure if mine worked till now i figured i could test mine and help someone else out on one side i had 10V and on the passenger side i had 1V when you turn the switch on it should make a click sound at the dash well at least mine does. you do know how to use a meter right???

I just had the lower dash portion of my 88 off and noticed the relay box for the rear window defrost is basically behind and lower than the rear defrost switch. 5 minutes to pull that lower dash off an its right there, small tin box.
There is also a clearly marked fuse for the rear defrost in the fuse box above the drivers left foot.

thanks guys, i do know how to use a meter and i hadn't thought of hecking the voltage at the window because my switch soesn't seem to be turning anything on. the little light doesn't light up on the switch. i don't hear the classic click sound my other XJ made when the rear defrost would get turned on. strange thing is i actually didn't think to check the fuse. I couldn't tell you why i overlooked that simple task, mabye because i've been through my fuse block with other problem i didn't think a fuse would be bad.

thanks for the leads guys i'll get on these and let you know the outcome.

Harold