Electric Windows & Sunroof - Fuse 29 keeps blowing - help!!

[eightfortee]

Hi Folks - my first post.

My 1996 BMW 840 Ci has developed a small but highly irritating issue. The fuse 29 keeps blowing and disables the windows and sunroof (I am not sure if this affects anything else, not that I have noticed anyway). On the reverse of the fuse cover - 29 doesn't seem to correspond to the windows/sunroof which is a bit of head scratcher....

It is tempremental - once I replace the fuse it might last a couple of days, but then it might only last a journey!

I am not by any means electrically minded, could it be something simple like a worn/broken wire where it goes into the drivers door perhaps or something else? It almost has the feel of a 'dry joint' situation although I am only speculating!

Anything anyone could advise? I am in West Yorkshire and would always welcome a chat if you are nearby.

Thanks
Rob

[Timm]

Fuse 29 supplies (as well as a whole bunch of relays) the General Module (ZKE), and that controls the windows and sunroof. The realys are:

Compressor Control Relay
Normal and High Speed relay for auxiliary fan
Auxiliary water pump relay
Air Conditioning relay

[eightfortee]

Hi Timm, thanks for the note bug any ideas what I need to do? Does this mean a relay is duff or that the general module needs replacing?
Mamy thanks
rob

[Timm]

I would start with the most likely candidate - the compressor clutch - does you A/C work? Try removing K19 (in the Front Power Distribution box) and see if the fuse doesn't blow any more.

[eightfortee]

I would start with the most likely candidate - the compressor clutch - does you A/C work? Try removing K19 (in the Front Power Distribution box) and see if the fuse doesn't blow any more.

Hi Timm, this seems to have cured the problem! My a/c did stop working before this started happening. Is it just k19 that needs to be replaced or is there possibly something else underlying?
thanks again
Rob

[Timm]

It will be the A/C compressor clutch itself - unfortunately they do get frizzled sometimes and the coil ends up looking like a disorganised bird's nest! The clutch is on the front of the compressor, and just like a fridge where the compressor runs for a while and then turns off in cycles, the compressor on the car does the same - using the clutch to connect and disconnect it from the ribbed belt.

I have heard that the clutch can be replaced separately from the compressor, but I haven't done this myself. If you are not mechanically minded a good A/C company could do this (possibly), but might just replace the compressor.

[eightfortee]

It will be the A/C compressor clutch itself - unfortunately they do get frizzled sometimes and the coil ends up looking like a disorganised bird's nest! The clutch is on the front of the compressor, and just like a fridge where the compressor runs for a while and then turns off in cycles, the compressor on the car does the same - using the clutch to connect and disconnect it from the ribbed belt.

I have heard that the clutch can be replaced separately from the compressor, but I haven't done this myself. If you are not mechanically minded a good A/C company could do this (possibly), but might just replace the compressor.

Thanks again Timm. Is the compressor the air-con radiator? As you can tell I am not mechanically minded! Will it do any harm in the meantime using without that k19 relay? Rob

[Timm]

No, it looks a bit like an electric motor which is stuck on the lower RHS front of the engine:



Leaving the relay out will cause no problems at all.

[legoman67]

the clutch can be replaced separately, but if your taking it to a shop to be fixed then most shops will simply replace the entire compressor.

[eightfortee]

the clutch can be replaced separately, but if your taking it to a shop to be fixed then most shops will simply replace the entire compressor.

Thanks very much for the advice! Really appreciated. Rob

- - - Updated - - -

Thanks very much Timm. Guess I need to find a new compressor! Really appreciate your help here, you know your 8 series! Rob

[Ausfahrt Oi!]

It will be the A/C compressor clutch itself - unfortunately they do get frizzled sometimes and the coil ends up looking like a disorganised bird's nest! The clutch is on the front of the compressor, and just like a fridge where the compressor runs for a while and then turns off in cycles, the compressor on the car does the same - using the clutch to connect and disconnect it from the ribbed belt.

I have heard that the clutch can be replaced separately from the compressor, but I haven't done this myself. If you are not mechanically minded a good A/C company could do this (possibly), but might just replace the compressor.

Dear Timm,

Im new in this blog, long time BMW driver and motorrad

[Ausfahrt Oi!]

Dear Timm,
Greetings. In the subject of AC compressor and power windows. My AC CLUTCH froze. Suddenly all windows and sunroof stopped operating from the inside controls. Now only work from outside . That is to open all or to close all.

how do I fix this? I applied the instructions above, or close. I removed K9 and swapped with another thinking it had damaged the relay. No luck .

Kindly, please share your experiençed opinion. This E31 1994 840 CI is a new project tô me.
thanx

- - - Updated - - -

I am ordering a new compressor and drier asap. After all this is SoCal. Try driving W/O AC HERE- it's a torture. Will issue be resolved automatically w new AC.

- - - Updated - - -

So the AC and the power windows and sunroof have a relationship, kinda funny.. Like a Pit Bull and a cat. Hard to grasp

[Ausfahrt Oi!]

Introducing myself and the user name. When in Stuttgart, I'd see this word all over the highways . But the name spelled and sounded so familiar to the result of eating too much beans.. So Just funny. I ride BMW bikes old and new, drive older BMW classic because life is too short to drive Boring new electric cars. ( Unles you are driving to Vegas, then you want a car that flies.

[caffeineplease]

I have an '95 840 and am having the same issue. Blowing Fuse 29. I also was having no AC. Removing K19 brought back my AC but the fuse 29 blew again. I understand I may need to replace/repair the AC Compressor. What should I do about the Fuses in the interim? K19 and Fuse 29. Thanks!

[ChrisFuture8]

I have an '95 840 and am having the same issue. Blowing Fuse 29. I also was having no AC. Removing K19 brought back my AC but the fuse 29 blew again. I understand I may need to replace/repair the AC Compressor. What should I do about the Fuses in the interim? K19 and Fuse 29. Thanks!

Replace fuse #29 and if K19 is not bad, reinstall it. Don't use your A/C until after you get the A/C clutch rebuilt. I had the same issue with my car when I first got it. On top of that, the auxiliary water pump valve body was stuck on so hot air was blowing on the driver's foot well all the time...especially when driving during summer time...not fun!

[caffeineplease]

Replace fuse #29 and if K19 is not bad, reinstall it. Don't use your A/C until after you get the A/C clutch rebuilt. I had the same issue with my car when I first got it. On top of that, the auxiliary water pump valve body was stuck on so hot air was blowing on the driver's foot well all the time...especially when driving during summer time...not fun!

Thanks. A follow up question. I could use the name of a good BMW repair shop for this classic. I see you and I both in the South Bay. Can you recommend someone?

[ChrisFuture8]

At Caffeineplease:

Sent you PM.

[killian665]

This happened to my 95 840. I replaced the compressor. Good to go.