XSeries-forum

Gah

Having never had the slightest electrical issue in the last 25k miles of ownership, it’s all gone wrong today.

I’m stuck at Watford gap devices on the M1, heading back to the South Downs..

Driving along at usual 75 cruise, I noticed that my indicators had stopped flashing. The alert lights came on, but no repeated blink. Both sides. Not a slow blink like a bulb gone, no flashing at all. I don’t like this.

Over the next few mins, noticed that some other controls weren’t responding either. The cruise control light is on, but can’t turn it off, for example.

I decided to pull in to the services to see if the lights on the outside were the same, and check the brake lights zzz

NOw it won’t start at all. No click, just dead.
The Headlights have come on and I can’t turn them off.
Central locking doesn’t work.
Cruise light is still on.

No idea what else - have called the RAC as I’m not happy getting back on the motorway even if it starts!

Any thoughts as to what’s gone on?!

It was driving perfectly and smoothly. No prior warning lights such as alternator at all

It’s a manual, 3.0d, no previous issues, service d about 1k miles ago.

Any suggestions welcome!

1st thing I'd do is disconnect battery - leave for 5 mins & re-connect.
That will clear faults.

A partial connection to computer can do some very odd things like this - check connection.

I'm presuming no alternator light came on ?  ... as low power will also cause a multitude of issues.

If you don't have tools to disconnect the battery, switch off... but DO not lock the vehicle, do NOT leave the keys in it either.

Maybe worth dropping drivers window open.

restart the vehicle, tick over 30 seconds so she does her diagnostics, switch off, remove key, wait 1 min & repeat...

This may clear the issue.

Unfortunately, this one will need a plug in diagnostic most likely.

Also bear in mind, these fat old ladies can get electrically stroppy some times.
I have the same model & engine, & she has done things like this before with no reason.... and it suddenly magically goes away.

Good luck Sir.

I think there may be some fuses actually on the battery cable at battery.... check these too.

How you get on bascule  i hope all sorted and you up and running again

Thanks all!

So, had no tools in the car, for the first time in ages, literally not even a screwdriver.  No choice but to wait the three and a half hours for the RAC man, at which point two of em turned up in separate vans.

During the wait - the headlights turned themselves off after about an hour and a half.  I also noticed the RPM needle was stuck at just under 3k rpm even with the keys out.  Electric windows DID still work, but locking didn't. Steering wheel controls some worked like the stereo, others didnt so the cruise light stayed on.  Weird af.

Anyway.  The first thing they did was hook up some power and confirm everything I was seeing, the no flashing indicators,  the lot.  Weirdly - the outside indicators WERE flashing, but the dash confirmation lamps were not.

They immediately agreed it could only be a 'can bus lockup' as too many differing modules were affected.  They had diagnostics hooked up etc and to be fair they then spent ages.  They disconnected aftermarket stuff such as my HIDS (which have been on for several years). They opened up the scuttle under the bonnet and checked down in the casing for all the modules to confirm no water ingress and all the cabling. 

They they dismantled in the boot and disconnected the battery, then disconnected glovebox fuses for the dashboard module etc. Added some power at the front, and the car immediately started.  Shut it off again, and reconnected the battery.  one by one they then reinstated the fuses, started again and then they spent ages on diagnostics, alternate load checks, the lot, followed by reconnecting the HIDS etc.  (Apparently some cheap aftermarket HIDS have leaked high voltage backwards and caused weird issues!  Mine were ok)

At this point, and having reset steering angle sensor etc, they pronounced it all good.  No fault found whatsoever.  Strangely, he said he sees this maybe once a week on Nissans, but couldn't recall ever having it on a BMW!

They spent probably a little over an hour all told, and I think were properly thorough..

At this point, I drove off, and two and a half hours later made it back home, no suggestion of any issue at all.

I have a suspicion, though.  I hardly ever used cruise control. Maybe three times since I got the car.  I did use it today, before the fault appeared, and it was the cruise light that wouldn't go out..  No proof of that, and they couldn't see an issue, but I didn't use it on the way back after!!

Thanks for all the feedback, I'm off for a whiskey now!!

Ben

Glad you got it going again and got home.
Shame they didn't find a faulty part then after fixing it you would have full confidence in the car well that is the way i think if you get me.