Jigsaw- electrical issues before I admit defeat ***SOLVED***

[bigwinn]

Evening all

Before I admit defeat and hand the car to someone who knows what they are doing... I'm going to ask if anyone has any thoughts on what could be the root cause of the electrical issues I cant resolve.

All ideas welcome!

List of issues:

Roof- unlatches ok windows drop- but wipers operate when roof motor kicks in and roof motor has low voltage and cant move roof
Wipers won’t work off stalk but screen wash does.
When wiper motor unplugged nothing works that have existing errors
When using the wiper stalk the windows stop working for 15 sec and interior lights go off
Sat nav screen doesn’t work but pops up
Windows move slightly (roof drop) when drivers heated seat triggered
Passenger seat works perfectly
Drivers seat motion not working completely (low voltage) and heated seat shows open circuit
Interior lights dim when these issues happen (roof motor and seat motors labouring)
Purple x2 relays strange noises when roof trying to operate

Apart from that, considering its been in bits for 2 years, the car is superb. Runs well, no warning lights at all. All lights, headlights, indicators are good no dimming/weirdness

I've tested the Kbus:

Kbus shows voltage stable at rest AND under component test with items that have problems

Earths checked x7 around the car- cant find any loose connections

All fuses removed one by one to see if that resolved the various issues (again to see if a component is causing the issue) but nothing changes

Modules tested (removed from power to see if the module is causing problems):

Roof module
GM5
Radio
Wipers
ABS/dsc
SAS
LCM
Clocks
Airbag

I've got a week or of work to do on it (servicing etc) and then have the fallback option of taking it to a local specialist for an MOT (which it will fail as the wipers don't work) so they can diagnose better.

I will reconnect to INPA in the am to see if modules are showing etc.

Come one come all! What else can I look at please?

TIA

Stuart

 

[bigwinn]

Oh and swapped GM5 over with two others to check that is not the issue

 

[enuff_zed]

Struggling to get my head round it mate if I'm honest, though electrickery is not my strong suit. I can find nothing in Newtis that links them all.
I tried to start by looking at the point where the roof motor is triggered to start running as that is where the wiper issue starts. Cannot find anything logical in that at all.
A random thought...................... can you try swapping the hydraulic pipes and the electrical connectors on the motor?
That way, what was the earth becomes the live for lowering the roof. If the fault changes then it may point to one of the wires in the motor circuit.
It's a wild stab, but no idea where else to start.

Starting to think you may need to actually pay an electrician.

 

[bigwinn]

Struggling to get my head round it mate if I'm honest, though electrickery is not my strong suit. I can find nothing in Newtis that links them all.
I tried to start by looking at the point where the roof motor is triggered to start running as that is where the wiper issue starts. Cannot find anything logical in that at all.
A random thought...................... can you try swapping the hydraulic pipes and the electrical connectors on the motor?
That way, what was the earth becomes the live for lowering the roof. If the fault changes then it may point to one of the wires in the motor circuit.
It's a wild stab, but no idea where else to start.

Starting to think you may need to actually pay an electrician.

To be fair I've not swapped them over so its worth a go

Steve also suggested (and I concur) that the common issue of wipers, windows and roof is GM5- so although I've checked maybe the wiring is duff...

 

[enuff_zed]

Struggling to get my head round it mate if I'm honest, though electrickery is not my strong suit. I can find nothing in Newtis that links them all.
I tried to start by looking at the point where the roof motor is triggered to start running as that is where the wiper issue starts. Cannot find anything logical in that at all.
A random thought...................... can you try swapping the hydraulic pipes and the electrical connectors on the motor?
That way, what was the earth becomes the live for lowering the roof. If the fault changes then it may point to one of the wires in the motor circuit.
It's a wild stab, but no idea where else to start.

Starting to think you may need to actually pay an electrician.

To be fair I've not swapped them over so its worth a go

Steve also suggested (and I concur) that the common issue of wipers, windows and roof is GM5- so although I've checked maybe the wiring is duff...

Have you checked the plug pins to the GM5?

 

[enuff_zed]

Oh, and here's another random thought. Are you sure the GM5 was the correct one? ie. was it definitely a Star 12 or a 5RD? Have you tried the other option?

 

[bigwinn]

Struggling to get my head round it mate if I'm honest, though electrickery is not my strong suit. I can find nothing in Newtis that links them all.
I tried to start by looking at the point where the roof motor is triggered to start running as that is where the wiper issue starts. Cannot find anything logical in that at all.
A random thought...................... can you try swapping the hydraulic pipes and the electrical connectors on the motor?
That way, what was the earth becomes the live for lowering the roof. If the fault changes then it may point to one of the wires in the motor circuit.
It's a wild stab, but no idea where else to start.

Starting to think you may need to actually pay an electrician.

To be fair I've not swapped them over so its worth a go

Steve also suggested (and I concur) that the common issue of wipers, windows and roof is GM5- so although I've checked maybe the wiring is duff...

Have you checked the plug pins to the GM5?

No- will put it on the list

 

[bigwinn]

Oh, and here's another random thought. Are you sure the GM5 was the correct one? ie. was it definitely a Star 12 or a 5RD? Have you tried the other option?

12 star for 12 star

 

[enuff_zed]

Oh, and here's another random thought. Are you sure the GM5 was the correct one? ie. was it definitely a Star 12 or a 5RD? Have you tried the other option?

12 star for 12 star

No reason why it would be, but have you tried a 5RD?

 

[bigwinn]

Oh, and here's another random thought. Are you sure the GM5 was the correct one? ie. was it definitely a Star 12 or a 5RD? Have you tried the other option?

12 star for 12 star

No reason why it would be, but have you tried a 5RD?

Don’t think I’ve got one but will check the parts pile

 

[bigwinn]

Never seen this before but the gm5 ops list is very interesting!

https://www.bmwgm5.com/GM5_Connections.htm

 

[BumpyZ4]

I think you are on the right track, either GM5, grounding issue or both. Since it sat so long it could have rodent damage to the wiring somewhere.

 

[bigwinn]

Going to run some clean grounds from the gm5 today to see if that makes a change

 

[colb]

Wiring for a GM5 here which may be of use https://www.bmwgm5.com/GM5_Connections.htm

 

[bigwinn]

Cheers col

 

[Trav]

Bigwinn, If you have a multimeter you could disconnect those earth points and use your multimeter to measure the current that would be going from the comb to the chassis (when operating those various items). Perhaps starting with that general module area. It may help you isolate it to an wiring section. If you don't see any excessive current draw that is dropping voltages to make your lights dim then it must be a restriction in power coming from the supply side. There is little commonality between all that stuff and faults though. The alternator is one of the few things that remains in circuit without flicking any switches or pulling in relays. I am not sure if faulty regulators and rectifiers can give spurious effects. But if your testing without running the engine perhaps disconnect it to be sure.

 

[bigwinn]

Some good points Trav- thank you I’ll have a go with that later!!

 

[bigwinn]

A few things done today- not really any further forward

Checked the earth drain on each point- no concerns
Checked the earth pins on the gm5- again no issues
Pulled a few more modules like the rain sensor- still nowt

The thing that confuses the bejaysus out of me:

Why does everything stop working when I disconnect the wiper motor???

 

[bigwinn]

As we are running out of options the final component swap out is a new fuse panel/distribution board. As it’s £15 it’s worth that for the spare fuses and relays alone

After that… it’s off to the specialists!

 

[bigwinn]

Inpa still struggles to connect to various modules in the car.

The engine based ones are visible but body/chassis not so