Recently, all four windows will intermittently not operate. Then suddenly they'll all work fine again. All four windows have relatively new window motors and regulators, I installed them less than a year ago, not that that's relevant to this strange problem. Wiring diagram shows front window motors go to BCU and rear window motors IDM, so considering all window motors are affected at the same time it seems unlikely it's either of those at fault. Have been fighting water ingress issues all over the car and have had electric issues before due to water ingress. Am doing a major tear down and overhaul this week to finally properly seal all the leaks but now I've also got this random window motor issue. Any ideas?

 

Water leaks into wiring and electronics can do a lot of strange things. My D2 came really cheap because of this. Corrosion inside the engine ECU as well as an (only one so far) electrical connector.

 

Following up on this a year later. My mechanic had a vehicle electrician (this is in Africa) solder some messed up points on the IDM and that seems to have cured the rear windows, in addition to some other problems—they work fine now. Now only the front windows don't respond... so maybe both the IDM and BCU were culprits after all, at the same time. Am driving from Uganda down to Cape Town to bring to the States, once I get back with the vehicle I'll replace the BCU and see if that cures the front window issue, as well as many other electrical gremlins I've had.

 

I just went through this, if you want to check my posts. Just got the BCU back today, one of the resistors broke. In my post there is a picture of it, white, near the plug.
I have a ton of info in my posts if you want to peruse. I feel like an expert now. If you do replace the BCU you have to get it coded to match the ECU and Odometer. If you want to ship the BCU to get diagnosed, the buy who fixed mine is at 609-333-3203. rurianassets21@gmail.com

 

This is great redrover, thanks for responding to this—will look at your other posts!