Z4 left side microswitch issue. URGENT HELP

[Deepseaskateboard]

I have seen also you need to replace the whole unit. Those parts will be hard to track down.

1. Do you want to bodge it? What if you can’t get the boot open?
2. It costs around £350 to have it replaced, recently reported in the forum.
3. There is a DIY video on youtube, you could try fitting the whole part yourself.

You can use bumper to spread the payments, get it booked in.

 

[Elliotharker1998]

I have seen also you need to replace the whole unit. Those parts will be hard to track down.

1. Do you want to bodge it? What if you can’t get the boot open?
2. It costs around £350 to have it replaced, recently reported in the forum.
3. There is a DIY video on youtube, you could try fitting the whole part yourself.

You can use bumper to spread the payments, get it booked in.

I agree with what your saying! I only bought the car 17 days ago from a motor trader! Just furious that this has happened

 

[Pondy]

The part you are looking for is the standard microswitch.

...which I presume has been spliced in before as it is part of the soft close cam motor and is not sold separately?

That makes sense to me.

The one thing I do know that is those microswitches have resistors inside them (presumably for the fault diagnosis electronics). But I don't know if all the microswitches have the same size resistors in them. @RobbiZ4 is the only person who will possibly know that.

OP...is there a BMW part number on the corroded microswitch itself? If there is it will almost certainly be one from another part of the roof and should be OK. Those can be bought cheaply and you will have to splice it in again.

Or go to the supplying dealer and set fire to their premises?

 

[Deepseaskateboard]

I agree with what your saying! I only bought the car 17 days ago from a motor trader! Just furious that this has happened

Oh, that changes things. Are they not liable then?
Have you raised it with them?

 

[Elliotharker1998]

...which I presume has been spliced in before as it is part of the soft close cam motor and is not sold separately?

That makes sense to me.

The one thing I do know that is those microswitches have resistors inside them (presumably for the fault diagnosis electronics). But I don't know if all the microswitches have the same size resistors in them.

OP...is there a BMW part number on the corroded microswitch itself?

No part number I can see I believe they did this on purpose knowing you'd have to buy the complete assembly

 

[Elliotharker1998]

Oh, that changes things. Are they not liable then?
Have you raised it with them?

I have messaged them however I can't let them know that I have been inside and took it apart to see where it failed can I

 

[bigwinn]

I agree with what your saying! I only bought the car 17 days ago from a motor trader! Just furious that this has happened

Why aren’t you taking it back to the trader??

 

[Deepseaskateboard]

I have messaged them however I can't let them know that I have been inside and took it apart to see where it failed can I

Depends how you phrase it.

"You have tried to diagnose and fix yourself, but it is not repairable and will need replacing"

 

[Pondy]

I have messaged them however I can't let them know that I have been inside and took it apart to see where it failed can I

I think it would be obvious to anyone that the corrosion to that switch hasn't happened in the last 17 days.
I would send them pictures and tell them to supply the part (complete) and you offer to fit it. You have come this far so you could easily replace it.
If they refuse, you tell them to fix it themselves or you reject the car and they have to refund you the full amount, as the car is not fit for purpose as it stands.
Doesn't matter that you have 'had a look' for the fault in this situation.

 

[Banners24b]

I replaced my entire unit last week for the same issue, plus one of the motors had a bad connection so was intermittent p/n is 51247354924 and was £350 + vat from local BMW dealer, took 2.days to arrive..softclose works perfect now.

 

[RobbiZ4]

You can buy new from BMW (I’ve a couple in the shed and can wire in direct

Single switches? Very interesting.

Seems that your discussion about microswitches for the roof shell, Mr @bigwinn.

 

[bigwinn]

Single switches? Very interesting.

Seems that your discussion about microswitches for the roof shell, Mr @bigwinn.

I think you are correct having read up on the boot latch mech- very interesting that they are now failing

 

[RobbiZ4]

Typically, the first failures occur from about 5-8 years of age. It's not the switches themselves, but the permanently bent wires that are the problem.

If they got repaired in the shown manner, the switches will brake. No way of return, no spare parts.

Post in thread '⌛E89: Boot Soft Close Failure Repair...'

Aug 24, 2025

Is there a part number for those 2 micro switches?

Not available at all on the world market.

However, they almost never fail, except due to violence by the owner. In this case, the owner must purchase a new locking system.

• RobbiZ4

• 

 

[Elliotharker1998]

I replaced my entire unit last week for the same issue, plus one of the motors had a bad connection so was intermittent p/n is 51247354924 and was £350 + vat from local BMW dealer, took 2.days to arrive..softclose works perfect now.

Hi mate where did you get this done please?

 

[Banners24b]

I did it myself, its very very easy about 15 trim clips to remove, 6 black bolts (3 each side) on and about 6 wire connecotors on the unit itself..its a sub 20 mins job

Life is made alot easier one of these

https://www.amazon.co.uk/dp/B08PCMX9MK?tag=z4fo-21

 

[Elliotharker1998]

I can defiantly do it myself as I've already stripped it to have a look! Could you tell me where you for it from for that price please?

I did it myself, its very very easy about 15 trim clips to remove, 6 black bolts (3 each side) on and about 6 wire connecotors on the unit itself..its a sub 20 mins job

Life is made alot easier one of these

https://www.amazon.co.uk/dp/B08PCMX9MK?tag=z4fo-21[/URL

http://

 

[Elliotharker1998]

I did it myself, its very very easy about 15 trim clips to remove, 6 black bolts (3 each side) on and about 6 wire connecotors on the unit itself..its a sub 20 mins job

Life is made alot easier one of these

https://www.amazon.co.uk/dp/B08PCMX9MK?tag=z4fo-21

Oh and defiantly getting those pieces trim pieces out was a nightmare! I will just buy it myself I can't be bothered going through the dealer

 

[Banners24b]

I used Marshals BMW in Hook, Hampshire..not sure where you are? But should find most dealers are a similar price..Sytner Stevenage are pretty good too and deliver

 

[Banners24b]

Oh one more thing @Elliotharker1998 there is an extra little torx screw that is directly behind the BMW badge, you need to loosen that out to pop the mechanism off or it'll fight you.

 

[Elliotharker1998]

Oh one more thing @Elliotharker1998 there is an extra little torx screw that is directly behind the BMW badge, you need to loosen that out to pop the mechanism off or it'll fight you.

Just phoned Williams bmw in Liverpool! I've managed to get it for £350 and they can supply the part for me today after 2pm made up