Rear Defroster

Hopefully someone can help me. My rear defroster does not work. I've checked the fuses and even replaced the relay under the back seat. The relay activates when the Rear Defroster button is pushed, but there is no power to the rear window grid. The grid appears fine too. Any guesses on where to look for a problem? I can't seem to find where the wiring harness from the relay to the grid runs and where the connections are which could be the problem. Any help would be appreciated.

Thanks.

Tom

You may want to check the heated backlight antenna module. Since the park avenue uses the defogg grid as an antenna, this module probably went bad. This module receives radio signal and powers the defogger when activated. You will find this module behind the rear left hand side sail trim(next to the backwindow).

You did not state what year and model your car is. Although what doggforlife stated may be valid for his, it is not valid for mine. My power antenna is not part of the defogger grid. A little more info if you please.

My rear defroster works but only every other grid line works, why.

Sorry, it's a 99 Ultra which has the antenna in the defogger grid.

I did replace the relay, but not the heated backlight module. The relay does click on and off when I turn it on. I would have thought that I would have terrible radio reception if this went bad, but that's not the case. I get stations on this radio that I can't get in any other car.

Thanks for the help.

Tom