Collective wisdom needed...

Worcester_spoon

Worcester_spoon

Senior member
 Basingstoke, Hampshire
Hi all,

Could I plug into the collective wisdom of the forum to help diagnose an issue on my mates car. 2003 M54B30, 90k miles.

Car starts and runs fine, but...

- Roof doesn't work (no light on the control panel, no whirring sound coming from the motor) - motor was moved to the boot 10 years ago
- High beam doesn't work, rest of the lights are fine
- Indicators work, but no clicking sound coming from the dash when they're flashing
- AC not working

I thought it might be a low battery charge, but charged it up over a few days and battery health checked - all fine.
Then thought maybe GM5 (although this doesn't feel like a GM5 issue) so spoke to the repair guys, and they said unlikely going to be that.

Wondering if it's a fuse/multiple fuses issue, or maybe a different control unit? Also possible it's multiple issues.

Would love any thoughts/experience. I can get access to a BMW reader if that's the only option.
 
How was the battery tested? A car I'm working on was fine, apart from a few things like that, including the roof not moving. New battery resolved all of the issues.
 
Are all the blower fan speeds working or is there just one speed?
If only one speed then car may have one into transport mode where it closes some systems down to conserve what battery power remains to start the car. If it is it has to be reset using software like BMW Scanner 1.4 or other capable scanners. Not sure your headlights and indicators would be down to this. Transport mode will close down the blower, roof and heated rear screen.
 
samZ4M said:
How was the battery tested? A car I'm working on was fine, apart from a few things like that, including the roof not moving. New battery resolved all of the issues.
Click to expand...
I have a battery tester, connects direct to the battery. Has been accurate before, but zeds and their sensitivity to batteries is a thing! I Might try swapping my battery onto his car as I know mine is good.
 
colb said:
Are all the blower fan speeds working or is there just one speed?
If only one speed then car may have one into transport mode where it closes some systems down to conserve what battery power remains to start the car. If it is it has to be reset using software like BMW Scanner 1.4 or other capable scanners. Not sure your headlights and indicators would be down to this. Transport mode will close down the blower, roof and heated rear screen.
Click to expand...
I'll check - was kind of hoping it was all one simple issue, but gut says might be different things...
 
I've done a lot of reading of subjects on this forum lately and a member called bigwinn mentions issues with the k-bus?
 
I'd guess k-bus, too.

I had an R53 like this (not quite the same electrical system, but close enough) - the A/C didn't work, the full beam and indicators worked, but the tell-tale lights on the dash didn't work. The radio often said 'disabled', and the instrument cluster lighting didn't work.

For me, it was a problem with the k-bus (the 'rev gauge' above the steering wheel on the Mini). The accepted way to troubleshoot is to isolate each k-bus component on the network one by one, and see when the fault disappeared.

I couldn't get a scanner to connect, as the k-bus was corrupting the signals out to the diagnostic gateway. I just went around unplugging things one by one until the diagnostic worked, and the dash lights etc all returned to normal.


The E46 is very similar, so there will be concept overlaps with that page, but you can see the kbus components here on page 16 https://ia800902.us.archive.org/26/items/BMWTechnicalTrainingDocuments/ST052 Body Electronics II/04b_E85 Driver Information.pdf (I can see the AC (IHKA), roof (CVM) and headlights/indicators (LSZ) are all on the k-bus on the E85, too.)
 
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