Hey folks,

I have a 2004 996 coupe. During heavy rain, I noticed the rear defogger / defroster working, however, maybe 3 or 4 lines work properly. Mileage is 53,000km / 33,000 miles. The rear defogger light stays on as it should until about 10 - 12 minutes (I forget exactly.)

What can be the problem? Anybody have this issue?

Thanks!

 

Scratches on the inside of the back window can damage the defroster grid. If your windows were tinted, or if tint was removed, it's easy to cut the individual lines of the heating element. If there's a break or scratch in the element, that "row" will not work.

If you inspect the window and see that the lines are cut/scratched, you can repair them. Here's an old Popular Mechanics article that explains how:
http://www.popularmechanics.com/cars...enance/4221212

There is a variety of products (search Amazon) you can use to repair the break(s), and there are a number of YouTube videos if you want to see someone else do it first.

 

Thanks, 5CHN3LL.

The windows were never tinted, at least to my knowledge. I will check the lines carefully to see if there are any breaks or scratches in the element.

 

Just to follow up:

The solution was very embarrassing. Turns out the fuse was missing. I popped it back in from the reserve fuses and voila! Problem solved.

The question of why or how it was missing in the first place is what bothers me.

 

Follow up #2:

I spoke too soon. Turns out only about 3 or 4 lines work. Any ideas on where else or what to look for?

 

Bump.

Any suggestions on where to begin troubleshooting? I can't seem to find any "visible" breaks or scratches on the lines. I'm not sure why or how only 3 or 4 lines work. There's got to be something more.

Perhaps a plug I can trace it back to or relay? Thanks in advance!