Electrical/Electronic Problems

P

phil45110

Member
 Cardiff
Had my 3.0si 2006 roady for 7 months now and have had an intermittent fault that has gradually got worse :( . First manifested itself as a reset of the clock to --:--, so researched on this forum and found that could be an early indication of a failing battery. Car always started ok, if a little sluggishly, so thought change battery and all will be well. Before had chance to change and during a drive about a month ago, speedo, rev counter, fuel gauge, temp and clock stopped working, all stuck where the instruments had stopped working. No indicator flashing in the car, but all lights working fine outside the car. Air con and heater fan ok, engine functioning fine, electric seats, heated seats, power steering, windows, radio all fine. Speedo stuck on 70mph, rev counter on 2700ish. Stopped, switched off engine no change, all frozen. Drove home, disconnected and reconnected battery, everything reset to normal. Thought, I must change that battery.

Bought a new Bosch S4 from Eurocarparts, fitted, thought my problems are all over. Err.....no they're not.

Problem still exists, same issue has happened another 3 times, never when I start car, always more than 20 minutes later, when driving. Have had all warning lights briefly illuminated and then frozen as above. Only electrical item that doesn't seem to work is the roof and the instrument panel. Has only happened when the roof is down, as it's a sunny weather only car, but don't think that has any relevance. Simply disconnecting and reconnecting battery has reset everything ok each time.

Any help, advice or similar experiences and remedies appreciated.
 
My guess is the voltage regulator is going bad with a heat related issue. It works OK when cold, but as the engine warms up it gets balky. I believe it's possible to put the instrument display into test mode where it will read out the actual voltage continuously. Drive around and see how much the voltage fluctuates. There's a post about test mode on here somewhere.

The regulator is mounted on the alternator but it is a separate part, so changing it shouldn't too bad a job.
 
Thanks bcworkz. Will do a search and find out about the test modes. Actually after I posted did a bit of digging about the instrument cluster and did read that it shuts down above 16v so makes sense. Not sure why the only other thing affected is the roof though.
 
The roof operation is still managed by an electronics module. I suppose as the voltage gets more out of range, more and more modules will shut themselves off. It is rather odd the roof module is one of the more sensitive ones. Hopefully the engine and airbag modules are much more tolerant of fluctuations!
 
I had a similar issue... Except my speedo wasnt affected. But my electric windows didnt work. Was due to a short on the kbus by my gaptec module.

Do you have one fitted? Seemed to occur after a few hours when power is passed through it.... So reset the battery and works fine initially.



Sent from my iPhone 5s using Tapatalk
 
aquazi said:
I had a similar issue... Except my speedo wasnt affected. But my electric windows didnt work. Was due to a short on the kbus by my gaptec module.

Do you have one fitted? Seemed to occur after a few hours when power is passed through it.... So reset the battery and works fine initially.



Sent from my iPhone 5s using Tapatalk
Click to expand...

Hi,
No gaptec installed. Only electrics installed are a dice mediabridge, which I have disconnected as a precaution. I've also recently had the door card off to fix a leak, and disconnected speakers, window switch etc. These were reconnected and are all working fine since. Excuse my ignorance, but what is the kbus and is it possible that I have disturbed something whilst carrying out the above?
 
Well got the display into test mode and monitored the volts. Idling in the garage a healthy 14.1 to 14.3v. Rev engine to 2500-3000rpm and no discernible change. Turned on various electrical equipment, lights, seats, windows, slight drop in volts then back up to 14.3v. Alternator seems healthy. Whilst doing this display, revs, fuel gauge randomly cut out a few times. Display off, so didn't see any change in voltage, but when power restored a momentary buzzing sound from the instrument panel. Still pointing towards the voltage regulator as bcworkz identified, but no way of proving this :(

Have booked it in for an inspection 2, brake fluid change and electrical fault finding at a nearby indy next week.
 
Finally got this sorted, was an instrument cluster failure. Had to be sent away to a specialist repairer and recoded to the car. Not a common Zed fault I've been told, and not cheap to repair :o
 
Thanks for the update & glad you got it sorted.

Can you post up where you sent it to for repair please, mines a similar age to yours, always handy to have the info to hand should it happen to me or anyone else.
 
TonyP said:
Thanks for the update & glad you got it sorted.

Can you post up where you sent it to for repair please, mines a similar age to yours, always handy to have the info to hand should it happen to me or anyone else.
Click to expand...

Bit of a long story really. Actually, not sure where it was sent. Car booked in at Forza West Indy in Chepstow. Diagnosed as cluster, then sent for repair to their normal contractor. They then reported back to Forza that it wasn't repairable. Forza enquired with BMW for price of new cluster - £700 plus VAT :o Long lead time from Germany, so Forza then searched for another repairer on the net who could get it working. 2 weeks later all done and recoded for the car :thumbsup: .

Will ask next time I'm there, where it was sent.
 
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