A hundred electrical gremlins

[Ergellegre]

Hello, I come cap in hand again in need of advice.

The gremlins:
Indicators work, but no click sound.
No indicator lights on dash - same with fog lights, hazards, full beam.
Instrument cluster backlight often does not turn off with ignition off and keys out.
5 beeps sound when ignition turned off.
Aircon not functioning.
Only max heater works.
Business CD shows time but is stuck at the time the car was turned on. Time shown refreshes with each time the car is turned on.
Roof not functioning.
Multi function steering wheel controls illuminated but not functioning.
Central locking not functioning.
Key fob lost all function over a period of a few days - new battery ordered.
When locked, alarm will sound after a few minutes.
Auto windscreen wipers not sensing rain, just basic intermittent function.
Windows sometimes operable with no key in ignition.
Windows often don't return to top position.

My Creator 310+ shows:
87 K Bus.
BE Data-filing difference to central light module.

The problems appeared after a rather hasty steering correction, I thought I might have snagged the multifunction steering retrofit wire I installed while turning, but it seems to be connected OK.

The car is booked in with MTek in Northampton for next week to have a new steering angle sensor fitted, but if I can't get the problems above fixed, I worry it could be expensive to have diagnosed by the garage.

Any advice appreciated.

 

[Ed Doe]

It would be very odd for it not to be linked to the recent work you've done to the mfsw - seems too much of a coincidence. I'd start by unplugging the mfsw electrics and see if you can reset the codes before paying money for a diagnosis!

 

[Mike6]

An old battery can show a host of problems. B
If the battery is getting on I would replace that first

 

[Ergellegre]

It would be very odd for it not to be linked to the recent work you've done to the mfsw - seems too much of a coincidence. I'd start by unplugging the mfsw electrics and see if you can reset the codes before paying money for a diagnosis!

Thank you. I'll make that job #1 today, disconnect the wire, clear the codes, then drive it down to Halfords for a new battery. Think I'll get a load of new fuses while I'm there too. Had fitted the MFSW a couple of months ago, but now you mention it seems clear it'd be suspect #1

 

[Ergellegre]

An old battery can show a host of problems. B
If the battery is getting on I would replace that first

Cheers. I'll fit a new one today. Not sure how long it's been in the car - I've only had it since Feb this year. Can't find any info on the 5 beeps after turning off ignition - reckon that could be low battery?

 

[Ed Doe]

Supposedly low batter can cause all sorts of wierd electrical gremlins, can your code reader do a battery test?

 

[Ergellegre]

Supposedly low batter can cause all sorts of wierd electrical gremlins, can your code reader do a battery test?

It can, and can also register a new battery - problem is with my K bus issue - the reader can't communicate with any of the body electronics except the instrument cluster and so fails to run a battery charge analysis. Just waiting around with a coffee now while whatever charge disperses having disconnected the battery so I can get the steering wheel airbag off and disconnect my MFSW.

 

[Ergellegre]

New battery installed, a decent Yuasa HSB096, and MFSW wire disconnected. However, all the problems persist. Going to change all the fuses now and see if that makes any difference.

 

[enuff_zed]

New battery installed, a decent Yuasa HSB096, and MFSW wire disconnected. However, all the problems persist. Going to change all the fuses now and see if that makes any difference.

Read the Project Jigsaw thread. Bigwinn had similar issues which initially we thought was a KBus fault or one of the modules on it.
Turned out to be an earth problem.

 

[Ergellegre]

New battery installed, a decent Yuasa HSB096, and MFSW wire disconnected. However, all the problems persist. Going to change all the fuses now and see if that makes any difference.

Read the Project Jigsaw thread. Bigwinn had similar issues which initially we thought was a KBus fault or one of the modules on it.
Turned out to be an earth problem.

Oh jeez. Just read through that Project Jigsaw thread - how many hundred ground points are there! I just wanted a rad manual sports car, I'm not ready for this! Guess I'd better order a multimeter.

 

[Pondrew]

I had a long conversation with my life-long friend regarding 12V DC electrics recently, as I am a novice when it comes to car electrics and DC voltage. He is one of those rare people who understands all things electrical and mechanical, no matter what it is. He has spent all his working life (40 years) as a service engineer for CNC milling machines and has a very practical brain.

He told me that in modern cars (with electronics) the earths are 'grouped'. Even though the car itself is 'the earth', circuits are divided into groups which share a common earthing point. The reason for this (so he tells me) is so if an earth fault occurs on one of a group of circuits, it doesn't affect others, otherwise the whole car would shut down.

But the problem with 'grouping' earths is that the manufacturer, when designing the electrical system, presumes a dead short causes the earthing fault, not a slightly 'dodgy' connection due to age, corrosion, terminals loosening, etc. So any of those can cause havoc with certain electronics associated within the 'group', as they rely on 'signal voltages' rather than full fat 12V DC which can amplify the issue.

I have no idea if the above is correct, but my mate knows a lot more than I do about most things and it makes sense when you hear of weird electrical problems.

 

[Jas- USA]

Generally, I'd say failing battery first. However, in your case with the electrical gremlins you're listing I'd have to say Failing Ignition switch. In that, you have way too many gremlins happening when your ignition is either off and/or the key is removed.

Goggle: BMW bad ignition switch

 

[DMike]

Generally, I'd say failing battery first. However, in your case with the electrical gremlins you're listing I'd have to say Failing Ignition switch. In that, you have way too many gremlins happening when your ignition is either off and/or the key is removed.

Goggle: BMW bad ignition switch

Or bad negative battery cable?

 

[Ergellegre]

Generally, I'd say failing battery first. However, in your case with the electrical gremlins you're listing I'd have to say Failing Ignition switch. In that, you have way too many gremlins happening when your ignition is either off and/or the key is removed.

Goggle: BMW bad ignition switch

Or bad negative battery cable?

Thanks gents. I did change an ignition coil recently, maybe I didn't reconnect ground properly... will check. Also thinking the boot / trunk cable harness is worth an inspection. A previous owner has attached what might be a trickle charger to the car - will need to see if that's shorting out - not entirely convinced it is a trickle charger though - it has a PCB and mini USB input. Weird thing. It did have a freyed and exposed cable in the boot, but after taping that up the gremlins are still all there.

Ignition switch isn't expensive, so have ordered one and will see if that makes any difference.

 

[Ed Doe]

Did you get this sorted in the end? Interested to know what the problem was!

 

[Ergellegre]

Did you get this sorted in the end? Interested to know what the problem was!

The problem was a faulty airbag ECU. It looked in good condition, but one pin was snapped - suspect condensation.

 

[enuff_zed]

Did you get this sorted in the end? Interested to know what the problem was!

The problem was a faulty central airbag module. I had some wheels on passenger seat that must've bashed the dash and broken the thing

Ah ha! So it was a module upsetting the k-bus.

 

[Ergellegre]

Ah ha! So it was a module upsetting the k-bus.

I've edited my last post as it wasn't quite accurate. It was the airbag ECU from behind the handbrake - which BMW no longer sell! One snapped pin.

So yes. First suspect was GM5, then ignition switch, but MTek in Brackmills hunted down the source of the gremlins to that Airbag ECU and sourced a mostly compatible used unit and coded it to the car. Airbag light is on, so I'll need to source an exact match - or maybe desolder and swap the working port onto my unit.

 

[enuff_zed]

Ah ha! So it was a module upsetting the k-bus.

I've edited my last post as it wasn't quite accurate. It was the airbag ECU from behind the handbrake - which BMW no longer sell! One snapped pin.

So yes. First suspect was GM5, then ignition switch, but MTek in Brackmills hunted down the source of the gremlins to that Airbag ECU and sourced a mostly compatible used unit and coded it to the car. Airbag light is on, so I'll need to source an exact match - or maybe desolder and swap the working port onto my unit.

If they coded it properly, VIN and system time, then reset the errors in INPA you wouldn't have a light on?
So have they done it correctly? Or did they not disconnect the battery first, in which case the satellite modules will have errors that need clearing too.

 

[Ergellegre]

If they coded it properly, VIN and system time, then reset the errors in INPA you wouldn't have a light on?
So have they done it correctly? Or did they not disconnect the battery first, in which case the satellite modules will have errors that need clearing too.
[/quote]

Hmm, funny you say that. I did find and clear faults from satellite airbags when I got home with my humble Creator 310+. They did my steering angle sensor too, which I needed to clear adaptions and calibrate myself once I got home too - it was super stiff above 40mph on the way home.

I'm not exactly sure what part number airbag ECU they used - just that they said they didn't think it was an exact match so I should look out for another on the used market and bring it to them to code in.