99 Park Ave rear defogger stopped working...

Hello,

The rear defogger stopped working at the start of Winter and I've been chasing it since. When rear defog button is depressed, light goes on, but no heating rear window. I checked fuses under hood, under dash and replaced the relay under the rear seat. The window grids are in excellent shape as are the wires in the trunk and the car itself, so what could be wrong?

I've heard of an RF filter module concerning the rear defog: Has anyone heard of this? What is it, where is it located and what does it look like? Maybe this is something to check. I've also heard that you should hear a discernable click or noise when putting the rear defog on, but I hear nothing.....and when it worked before, I don't recall hearing anything either. Appreciate your responses.

Thanks and Happy New Year!

You can easily fix this porblem.
I have a similar PA with problem resolved recently.

Look for the module inside post between the driver side back door and rear window. Pull out the inner covering with care and you can inspect for burnt wiring/defective unit.

My problem was a burnt wire which was re-attached.

Thanks I'll try that......and I bet that's probably it too. I had the understanding it was under the molding behind the passenger front seat and didn't find anything! It's a little annoying problem, probably too easy to fix, just extremely difficult to find. I'll keep you posted, thanks for the tip!

Rali,

Many thanks for the tip! I checked and sure enough, the plug toward the backside was burnt. I pulled the module out and cleaned the connections along with the burnt plug and it started working again!

Just for good measure, how did you repair yours? Did you have to splice the wires? Just wanted to know because if it does burn out again then the plug is probably the culprit. It is pretty burnt, but still working at the moment and I just plugged the melted end back in after cleaning it. I will be lucky if it stays working, but get the feeling it will do the same before too long. Next time I get to the junkyard, I'm going to get another plug just in case.

Again, thank you! I've been chasing this annoying problem for some time now.

Thanks for the post. I have a 97 PA and had the same problem. I was really scratching my head until I found your answer. Mine had the same burnt wire and connector. Was able to clean it up enough to get it working. Will be looking for a junkyard replacement as soon as time permits.

Sharing information and knowledge is the greatest. Hope to be able to shed some light on someone else's problem some day.

Thanks to everyone who posted in this thread, some good info here! Since the thread has reach a conclusion, it will be closed from further posting, but can still be recovered by doing a search for “rear defogger”.
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