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2001 E46 325Ci - Cluster, heating control and stereo contol illumination not working

4K views 14 replies 3 participants last post by  Mr_Beemer 
#1 ·
Hello,

I'm experiencing an issue whereby the lighting behind the gauges on the cluster isnt working when I turn the lights on. The digital displays are working fine (i.e. mileage readout and radio) and the steering wheel control buttons illuminate orange just fine. The LCM itself lights up to show the different light positions as do the hazard light and door lock button, however the stereo buttons and climate control buttons do not light up orange.

I have run the Test 2.0 on the cluster and everything works other than the dials themselves lighting up.

I have disconnected the battery overnight and reconnected - still same issue.

I have checked all the fuses and they all look fine too (there are 3 fuses I think can't remember the numbers off hand)

I have run out of ideas on this and have searched and searched for answers, some posts suggest LCM others suggest GM5 however I dont believe I have the most common symptoms for failure on either of these - I'm happy to be wrong about that - just desperately need to know whats wrong so I can get it fixed.

Any help advice or guidance would be most appreciated
 
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#11 ·
Check wiring diagram to find out how illumination is managed: WDS BMW Wiring Diagram System - 3 E46
Dimming is managed by the Combi cluster. Indicator lights (high-beam, turn indication etc.) are sent via K-bus from lightning module to the combi cluster.
How the illumination is controlled, I didn't find out yet, but since the K-bus is connected to stereo, AC/Heater panel, lichtning module, combi cluster and more, I suspect the lightning module is malfunctioning.
Now there must be checked how the other matters are illuminated...
 
#12 ·
I checked last night and nothing dims when I turn the headlights on - just a case of the dials, stereo and ac/heater buttons not illuminating at all. From what I had researched previously I thought it may have been K-BUS related and disconnected the battery overnight, touched postive and negative cables whilst unattached to the battery to fully ground out then reconnected but same issue. Other common faults that cause K-BUS issues such as corroded CD Changer Cable and Electric Seat harness are also fine. If it is the LCM at fault I assume a diagnostic check would pick up on this and I think I am going to have to get one done to get to the bottom of this
 
#13 ·
Now the really weird interesting thing I noticed this morning when driving in to work, it was a bit dark so I had my lights on, pulled into the car park at work and went to put up the handbrake and noticed that all the illumination on the cluster started to work! With the lights still on, as I pulled the handbrake up the illumination went off again. If I put the handbrake all the way down it worked again. Now I fitted a centre console with an arm rest back when I first bought the car - and I'm thinking maybe a wire or something got snagged when fitted and its causing some sort of short circuit or something. Although I have had no fuses blow. It must be something like that unless there's some sort of setting linked to the handbrake and the console illumination?
 
#14 ·
The handbrake warning light is linked to the cluster so id start looking at the little switch under the handbrake gaiter.
You may have shorted an earth wire there.
 
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