Witch Switch?

N

na51hog

Member
Hi,

Firstly, a quick note of thanks to Robbie and others on here who helped me diagnose and fix a problem hall sensor that was causing my Z4 E89 roof to fault. After a couple of months of faultless operation, I now have an intermittent roof problem as follows:

  • On opening, the rear screen roof panel folds over the top roof panel and then the operation stops. It stops the moment before the boot lid is going to open.

    I get a bong and a red light.

    No fault codes are generated as indicated by subsequent scans of the ECUs.

    If I wait a minute or so and press the roof button again, the boot opens and the whole operation completes normally.

    Subsequent immediate repeated cycling of the roof normally works fine.

The fault will re-manifest itself after a couple of days – usually the first operation of the roof that day.

This is my thinking so far:

  • No fault code generated means it is unlikely to be a hall sensor – so microswitch?

    The intermittent nature of the fault and its timing (usually the first operation of the day) suggests a sticking switch?

    The consistent position of the roof when it stops would indicate to someone who understands the sequence of operation of the sensors and switches which switch or pair of switches it would be?

The roof always stops in this position -

zNr7ZT1.jpg

I believe there are 8 microswitches and, for no particularly good reason, I thought it might be switches 2 and/or 3 in this diagram?

7hMtiiq.jpg

The parts are available at my local BMW service department for around £26 each, so not too bad, with equivalents on eBay being about £10 more.

Can anyone here increase my chances of replacing the correct switch(es) to minimise my investment in time and money – or even tell me it is not a microswitch problem at all?

Thanks
 
I can't help at all, but your car looks stunning! Is that a quad exhaust poking out the back?
 
tiglon said:
I can't help at all, but your car looks stunning! Is that a quad exhaust poking out the back?
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Oh s**t, you are my man of the month. :rofl: :rofl:

@na51hog I will come back soon this evening.


Btw, nice thread topic ("witch")
 
tiglon said:
I can't help at all, but your car looks stunning! Is that a quad exhaust poking out the back?
Click to expand...

Thanks, and yes, at the risk of hijacking my own thread!

Eisenmann Quad Exhaust - Sport (Pro Race also available) plus matching carbon fibre diffuser.

http://www.eisenmann.co.uk/index.php?route=product/product&product_id=632&search=e89

wCbOpR4.jpg

Gxq2ww9.jpg

EtakwtF.jpg

My second choice would have been your Valencia Orange - even more so on a BMW i8!
 
na51hog said:
I get a bong and a red light.
No fault codes are generated as indicated by subsequent scans of the ECUs.
[...]
This is my thinking so far:
  • No fault code generated means it is unlikely to be a hall sensor – so microswitch?
Click to expand...

  • This assumption can't be taken in every case, but in this special case you are on the right path.

    na51hog said:
    The intermittent nature of the fault and its timing (usually the first operation of the day) suggests a sticking switch?
    Click to expand...
    Absolutely correct, I made the same experience on several Z4 in the past.

    na51hog said:
    I thought it might be switches 2 and/or 3 in this diagram?
    Click to expand...
    Correct.

    Congratulations, all in all a very good diagnose!

    What you can't recognize with your tools, which side doesn't work correctly. With my "Y3 Diagnostic System" I'm able to detect the delayed signal on it's individual chart.
    https://z4-forum.com/forum/viewtopic.php?t=129048


    20210826_182508_sm.jpg
    20210826_180603_sm.jpg
    20210826_173515_sm.jpg
    20210826_181121_sm.jpg
 
"Correct.

Congratulations, all in all a very good diagnose!"

Praise indeed from you, thanks! - you are the supreme roof whisperer :D

From your amazing post -

OxhYEIS.jpg


Since I don't have your incredible machine I will replace both switches to make sure I fix it.

And so, to my last, rather mundane question - which I am sure has been answered in this forum before - can I get to the switches without any major drama or disassembly?

Thanks again for your incredibly comprehensive replies. It's always a pleasure to talk to a true SME (Subject Matter Expert), we are very lucky to have you on this forum. :happyclap:
 
I don't think there would be working E89 roof by now without Robbi. :thumbsup: :thumbsup:
 
RobbiZ4 said:
na51hog said:
... can I get to the switches without any major drama or disassembly?
Click to expand...

You didn''t check your inbox, right? But you should... :rofl:
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I did after your gentle :poke: here, and many thanks.

I think you have Private Messaging disabled as I couldn't reply to you? In any event, message gratefully received and understood :D

You will probably throw your hands up in horror :o , but before I embark on the fix/f*ck up of a lifetime, what do you think of the idea of the application of a small amount of WD40 to each switch in situ, to try and relieve the stickiness? Any likelihood of that working, or is it more likely to put the switch out of action completely and forever? :cry:
 
na51hog said:
I think you have Private Messaging disabled as I couldn't reply to you?
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Ups, didn't know that - corrected. :D

na51hog said:
..what do you think of the idea of the application of a small amount of WD40 to each switch
Click to expand...
Nothing, because with these internally very tiny microswitches I would expect their EOL. :rofl:

But if so, you'll have to have it replaced too. :roll:
It's an interesting and well-read theory to revive hardened rubber with WD40.

In that case you can also try to use a face cream, that might smell better. :thumbs up
 
RobbiZ4 said:
na51hog said:
I think you have Private Messaging disabled as I couldn't reply to you?
Click to expand...
Ups, didn't know that - corrected. :D

:thumbsup:

na51hog said:
..what do you think of the idea of the application of a small amount of WD40 to each switch
Click to expand...
Nothing, because with these internally very tiny microswitches I would expect their EOL. :rofl:

I thought that would be the case :headbang:

I will get to it next week and let you know how I get on. I will take some photographs as I progress which I will let you have. They may be of use to you for those yet to tread in the footsteps of the master :)
Click to expand...
 
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