Originally Posted by beer ad
It does absolutely nothing now (exc. HU illum and fan)..I have a blank screen. Prior to battery replacement it worked for short periods of time for 3 days after it first went out. When it first went out, I was 15min in on my drive from ATL back to CLT (that was a fun 3h!). It didn't boot back up until the next morning (about 12h rest) , even after multiple attempts to stop/start the car when I got home. Sat overnight and ran for 10min, then shut down. That continued until I took the car in for battery replacement on the 4th day.
I guess fan would also be controlled by different circuit.. makes sense
Hard reset was the first thing I tried, and have done countless times since. I still need to check voltage on it to see if it's getting power..I don't think it is. If it's not, I need to figure out why. My SA suggested MOST boots in sequence, and I do have the iPod module that I installed a few years ago, but it hasn't given me any problems. I have thought about looking at that...
I would definately check for loose wires in the back first; take it apart to the point where you can reach your hand behind and adjust the various harnesses etc.
The MOST network is for audio/communication; i.e. I think
you can have the MOST loop broken or invalid and still get visual on the headunit. The important thing about MOST is that it's a closed loop fiber network, and the signal source and signal termination must be by the main communication device, i.e. the head unit.
There's generally a method of the MOST loop device sequencing, i.e. a specific order, but I don't believe it's really THAT important. I added a sirius unit to my car, and did so by just using the next available spot in the MOST block. Mine was a tad confusing because my configuration spans both blocks, but so long as they loop in to one other and terminate back into the head unit, no problem.
I suppose if there was a fatal error in the MOST loop it could cause bootup issues; but again I would think you would get video to the screen. Various errors, etc. but you should at least see the BMW logo. I believe there's also a MOST diagnostic port under the driver kick panel; make sure that didn't come loose or is missing the termination cap. You can also check the MOST blocks, which are behind the driver side rear passenger seat, on the outermost section of the seat [by the door]. If you have fold down rear seats it's a piece of cake, if you have single piece seats... loads of fun.
Do you have the HK/L7 system? Did the dealer give any insight into fault codes as to why the unit is bad? I have the extended warranty but opted to not pay additional for the radio/nav; assuming that if and when it goes bad i'll swap for the CIC.