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Discussion starter · #21 ·
Car would not fire this morning. Pulled ALL wires off the K-bus and put volt meter on the bar. Added wires one at a time monitoring voltage. Finally found one that knocked it down and left that one off. Car started right up. But ZERO dash function still. Central Locking and key lock/unlock are both working fine AND the car starts. Memory and Rain sensor are about the only circuits I have tested. Door locks, trunk lock, headlights, driving lights, sunroof, power windows, radio, seats, wipers, turn signals ALL seem to be working. I have the reading light left on right now to test and see if the "sleep" function appears to be working.

What am I missing other than the cluster itself being the culprit?
 
Discussion starter · #22 ·
Pulled the cluster after disconnecting positive and negative cables. Did hard restart of the battery by touching +/- cables together. Put cluster back in and reconnected battery.

No dash functions. But the red light that had picture of air bag that was coming on before does not. Only ABS light. Locks/unlocks/starts and runs. Everything that I've tested seems to work (including rain sensor, verified with hose). Air conditioner doesn't come on and key chime doesn't in addition to the no dash. AC shows degrees in C.

My next step is to find a shop who will scan with the BMW tools and let me know what module isn't working unless anybody has any solutions that I haven't tried.
 
Discussion starter · #23 ·
How constant should voltage on the K-bus be? When I first embarked on this endeavor it was bouncing between 8 and 13 volts. By leaving whatever wire I have off out of the picture, it is significantly MORE stable. But it moves between 13.2 and 13.7 volts. This seems to me like something is still whacked that I have attached.

I think the circuit that I have disconnected may be the multi-restraint controller which I'm guessing is side airbags and seatbelts possibly?
 
Discussion starter · #24 ·
After identifying everything else as working except the dash I decided to have a local shop do a DIS scan. The dash (as I had concluded) had failed. Will update this when it's repaired.
 
How constant should voltage on the K-bus be? When I first embarked on this endeavor it was bouncing between 8 and 13 volts. By leaving whatever wire I have off out of the picture, it is significantly MORE stable. But it moves between 13.2 and 13.7 volts. This seems to me like something is still whacked that I have attached.
The k-bus is suppose to bounce between battery voltage and 1/2 battery voltage when measured with your average multimeter which does 2 to 3 reading per second. If you where to look at the k-bus with an oscilloscope it goes between battery voltage and down to zero.

With your symptoms it sounds like a dead cluster. They are starting to become more common with age. Most of the ones I've seen so far have been repairable.
 
Discussion starter · #26 ·
I narrowed it down to either the cluster or the multi-restraint module. Not wanting to throw parts at it, it went to a local shop where they diagnosed a bad cluster. Which I had replaced and probably paid too much! Thanks for the help and maybe this thread helps somebody else in the future.
 
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