BMW 3 Series E46 Rear Defroster Not Working Diagnostic Steps and Testing Procedures 

That is awesome! Glad I could help :)

That is great news :) I am glad it was nice and simple.

Thanks for the video. It was Actually my fuse that forsome reason wasnt providing power.

5/5 star!!!! Well explained! Can you please make a video on how to change diagnose parking distance sensor on an e46. Much appreciated!

This was a perfect instructional tutorial on troubleshooting the rear defroster. Nice work. Going to take advantage of it this weekend and figure out what's going wrong with my my 2003 325iT

Hello, Some of the strips are for the remote control and the AM FM so for those you will not see any reaction with a test light. Since you do see light at the top two then the relay is activating. Check on the far left and right of those strips. Also with an volt meter you can ohm out the strip to look for any breaks. If you do get power on one side of the strip and you follow it along and you loose power then this would be a break in the circuit and that leg would not heat. Hope this helps :)

Thanks again. In my particular case, the top two strips light up the test light BRIGHTLY, across the entire strip. In your video, your 12v test light seems dim, whereas mine is as bright as if was hooked up to the battery positive. I also saw some light blue sparking at the far right side of the 2nd strip. I thought it was a bad connection, but now i'm starting to think I'm getting too much power which is causing some kind of malfunction.

Thank you for the great comment :) My E46 unfortunately does not have PDC but I can keep an eye out for an opportunity to make a video like this for you. I can post some instructions on how to remove and install them. Diagnosis of these are more difficult as the BMW tester would be needed to check the status of the PDC system and check the signal to each sensor. I plan on purchasing the GT1 for home but have not yet had the funds for it :) Can you post the last seven digits of your VIN? TY :)

So even though you are getting power the rear defroster does not seem to be heating up? It could be a bad ground for the rear glass. I would definately take a good look at the ground as the ground through your test light is good. It might be brighter due to the ground issue that my vehicle does not have. You could also run your own ground to see if this corrects the problem.

Tank’s

Since I have full brilliance of the light at both ends of the two working strips, I believe this is suggesting an open, or poor connection at the ground circuit on the window.I'm guessing the ground connection is the left side of the window if you're looking from the rear. I wonder if this may also be the cause of the battery going bad recently.

On my wagon, the first thing I tested after checking the fuse was strips with a test light without checking the relay. My top two strips light up my test light (brightly) but no strips below. Is the continuity in the circuit broken if one of the strips is broken?

Hi, your video was helpful. but didn't resolve my problem.

Hi, Can you tell me where the relay is on the E46 wagon (Touring)? Thanks

That's a good video more grease to your elbow ...