[Scrib]

Hey all. Have a rather interesting problem with my 335 coupe and was hoping someone has an idea, though, etc.

Bought my coupe used (2007) back in December with just short of 10K on the clock.

In the last two weeks, I've been having what I would consider electrical issues with the car. Basically, at random (although becoming more common it seems), my seat belt extender, windows and outside mirrors all stop working. It may be days before they start working again and will work fine and then go out again. Today, I couldn't get the windows up and drove through a thunderstorm. Or I'll fold my mirrors and they won't unfold. Not good.

I've tried everything and took the car to the dealer once, and of course they couldn't replicate the problem. They did reprogram the FRM which they say controls all those functions. No luck.

I took it back in today and showed them the issue (it was happening all weekend and was fortunately still there at the dealer) and they immediately started to do a scan. They did comment that they've never seen this before (go figure).

Any ideas? I'm guessing this is going to be tough to figure out. Was looking to the community to get thoughts.

[HighVoltage]

Originally Posted by Scrib

Hey all. Have a rather interesting problem with my 335 coupe and was hoping someone has an idea, though, etc.

Bought my coupe used (2007) back in December with just short of 10K on the clock.

In the last two weeks, I've been having what I would consider electrical issues with the car. Basically, at random (although becoming more common it seems), my seat belt extender, windows and outside mirrors all stop working. It may be days before they start working again and will work fine and then go out again. Today, I couldn't get the windows up and drove through a thunderstorm. Or I'll fold my mirrors and they won't unfold. Not good.

I've tried everything and took the car to the dealer once, and of course they couldn't replicate the problem. They did reprogram the FRM which they say controls all those functions. No luck.

I took it back in today and showed them the issue (it was happening all weekend and was fortunately still there at the dealer) and they immediately started to do a scan. They did comment that they've never seen this before (go figure).

Any ideas? I'm guessing this is going to be tough to figure out. Was looking to the community to get thoughts.

FRM is the first thing I wouldve looked at as well as those are all located on the same LINbus trunk. Have they tried replacing the FRM? Did they check to make sure the common reference is secured (i.e grounded properly)?

I dont know how much information they can pull from the FRM but LINbus(2.0) does have a fairly decent diagnostic suite (transport, signal and user).

After that a check of the LINbus trunk itself to see if there is an issue with the physical layer (e.g wire is frayed and shorting) but that would probably take alot of tearing things apart.

[Scrib]

Hey, thanks for the info.

Didn't get any details but they did order the footwell module. I didn't get specifics on if they determined it was found defective or if this is the first step to try and "fix" things.

Fingers crossed.

[Scrib]

Well, I'm pretty much at a loss here.

The dealer ended up ordering the footwell module and after replacing it, the problem did not go away.

So they ended up disconnecting everything that is attached to the footwell module and "determined" that the culprit was the passenger side mirror motor. They said that if one device goes down, it takes everything else down???

So I got the car back and everything was working great. That is until this morning when the problem came back, identical to before.

So now I fear I have a bigger issue on my hands, something that may never get resolved.

[GMWNashville]

suppose it could be related to consumer shut down..though highly unlikely. hmm ill have to think on this one a bit...

[HighVoltage]

Originally Posted by Scrib

Well, I'm pretty much at a loss here.

The dealer ended up ordering the footwell module and after replacing it, the problem did not go away.

So they ended up disconnecting everything that is attached to the footwell module and "determined" that the culprit was the passenger side mirror motor. They said that if one device goes down, it takes everything else down???

Its possible depending on how the transceiver failed. Its a single wire bus.

So I got the car back and everything was working great. That is until this morning when the problem came back, identical to before.

So now I fear I have a bigger issue on my hands, something that may never get resolved.

Take it back in. This is going to take some work to isolate. It could be a systemic issue (e.g Mechanical->Electrical). Good luck.

[Scrib]

They've had it now for almost a week. They think it was a bad connection at the junction (fuse) box. They've made the repair and have asked to keep it for a few days to test.

Fingers crossed.

[aerodyte]

Originally Posted by Scrib

They said that if one device goes down, it takes everything else down???

What the??? Remember the old style christmas tree lights? One bulb goes out, the whole thing doesn't work? And this is progress?

My car is at the dealer right now because my central locking will not work. But its strange because the remote will not lock or unlock the car (except for the trunk), and the lock switch in the dash will lock but not unlock. Would this FRM cause this behavior? It's really embarassing. I'm driving up to the gas station. To get myself out of the car, I have to lower my window, take out the steel key and unlock the door from the outside while I hang out my window. People are looking at me. hmm I'm wondering what they are thinking? BMW aka (Bayerisher Mist Wagen)

[Neon21db]

Originally Posted by Scrib

Well, I'm pretty much at a loss here.

The dealer ended up ordering the footwell module and after replacing it, the problem did not go away.

So they ended up disconnecting everything that is attached to the footwell module and "determined" that the culprit was the passenger side mirror motor. They said that if one device goes down, it takes everything else down???

So I got the car back and everything was working great. That is until this morning when the problem came back, identical to before.

So now I fear I have a bigger issue on my hands, something that may never get resolved.

How much were you charged by the dealer so far?

[HighVoltage]

Originally Posted by aerodyte

What the??? Remember the old style christmas tree lights? One bulb goes out, the whole thing doesn't work? And this is progress?

Yes it is. I can also recall when you always had to use a key.

The alternative, with the same feature set, would be a star topology where each device has its own wire(s) back to the Master. A bus is significantly more reliable, cheaper and easier to maintain than a star topology.

Originally Posted by aerodyte

My car is at the dealer right now because my central locking will not work. But its strange because the remote will not lock or unlock the car (except for the trunk), and the lock switch in the dash will lock but not unlock. Would this FRM cause this behavior?

Yes its possible but its not the only component in the process.