[0zma]

Hello!

So I recently purchased a 2011 E90 that came with an assortment of electrical issues. Purchased the car since engine sounded/ran well and it was cheap figuring I can sort out the electrical on my own.

Car runs well, drivers and passenger windows work, lights all work (has xenons and those work). The problem is the side mirrors and rear windows don't. Control from the drivers seat does nothing for them, used back seat windows controls and those don't work either. No codes for any of this.

First, I checked fuses and all associated fuses checked out fine. Next, I tried unplugging one/both side mirrors thinking a short was causing the LIN bus to fail - nothing. Changed out the driver's control switches - still nothing. Swapped out drivers side mirror thinking the motors for both side mirrors and rear window regulators are dead - still nothing.

So now I'm thinking it's a problem with the FRM programming and I wanted to re-flash it to factory. Followed a YouTube guide, got to INPA vehicle information step and it raised lots of questions.

Since most guides say to use the CAS backup to flash the FRM, I'm not trusting my CAS since it's got a blank VIN and the data is prior to manufacture (car was manufactured 2010) and might have been replaced? FRM might have been replaced too (appears sometime in 2021)? I have no idea the history of this car so can't say what has/hasn't been replaced by the previous owner. Now, I'd appreciate help on next steps to hopefully resolve this weird issue.

[0zma]

So started my digging into what parts were put into the car and looks like the RealOEM specs call for FRM3 and JBE3 modules, but one of the previous owners put in a FRM1 (61356961134) and JBE2 (61359176877) module.

Question now is, should these work? Adaptive headlights likely won't with the FRM put in (although it's a Xenon module) but would the JBE2 possibly not like the LCI mirrors?

I'm going to try re-coding the JBE to vin and reflash to see what happens but thought I'd ask here.

**UPDATE**

So re-coding JBE didn't do anything. Ended up finding a parts dealer here with an FRM3. Re-coded that and now mirrors work and fold! Rear windows still not working though. I'll troubleshoot that separately as I wouldn't be surprised if the regulators on both are dead.

TLDR: While modules like the FRM are technically backwards compatible, some functions are shared and others are not. Save yourself the grief and man hours trying to troubleshoot and make sure the right part is in the car and check if the previous owner did some jank parts swapping.