[roarf]

As the title states, my rear defroster is not working at all. First thing I checked was the fuse (that was a PITA), which is fine. Which C-pillar is the wiring behind and how do I remove the C-pillar without breaking anything?

Also, the battery is new as of October, but the nimrods that sold me the car did not put an AGM battery in. Would that have any effect on this? The CCA, CA, an Ah all seem correct, compared to the two batteries Interstate suggests when you search by vehicle.

One thing that seems a little odd is the lines on the glass look really faint. See photo below. Can't tell if the tint is just playing tricks on my eyes or the lines really are that faint. Really hope the tinter didn't wet sand the defroster lines to get the tint to sit flatter...

[mecheng77]

Was the tint recently done?

Those lines look discontinuous, there a way to check continuity from one end to the other

Check out this video

https://youtu.be/r9NQ46ckgYw

[TrboMike]

I also vote there was tint removed (the wrong way) or someone was super aggressive cleaning the back window.

Is this a droptop or solid roof car?

[jzeiler4]

That is what happened to me on my E46 vert. 2004 to 2017 the tint was there and I removed it with the ammonia cleaner and black bag method. It came off OK but only two strands of the defroster still worked while before removal they all worked.

[roarf]

Originally Posted by mecheng77

Was the tint recently done?

Those lines look discontinuous, there a way to check continuity from one end to the other

Check out this video

https://youtu.be/r9NQ46ckgYw

Thanks for the link. Not entirely sure when it was done. Sometime before I bought the car, which was last October.

Originally Posted by TrboMike

I also vote there was tint removed (the wrong way) or someone was super aggressive cleaning the back window.

Is this a droptop or solid roof car?

It is a coupe.

[aerobod]

I think from the perspective of fixing the problem, a replacement rear window is probably the only option. An automotive glass specialist is probably the best place to take a look and make an assessment.

[MarcoZandrini]

The C pillar covers are easy to remove. As I remember they they are held in place by plastic clips that are similar to those holding the door cards in place.

https://www.realoem.com/bmw/enUS/sho...diagId=51_9435

[roarf]

Finally got a chance to take the C-pillars off. I don't see any physical issues with the wiring and the defroster lines actually look ok from the inside. I want to check the resistance between the two electrical connectors. Does anyone know what it should measure? I can't find anything in ISTA.

[mecheng77]

Check for open circuit

[roarf]

I can't get a reading on any of the resistance settings on my multimeter. It just reads 1, which means open circuit. Tried checking for power and the incoming connectors are showing ~8.5 V. Looking like the window itself is the problem.

[roarf]

It was the rear window. Confirmed by the BMW dealer. They also stated that the REM wasn't providing enough power to the defroster, but that it might have gone into a protection mode from sensing an open circuit. Replacing the window fixed the problem. No need to replace the REM, I cleared the codes and tested it and it's working now.