Z4 Side mirror malfunction : fixed

[Jowenkim]

Hi all,
If any one has a problem with wing mirrors, hope it helps.

I recently got a lovely deep sea blue Z4 35i, second hand but nicely tuned by the previous owner.
A few days after having it, I realized left(passenger side in NZ) wing mirror was not controllable at all, no-folding, no-tilting while right (driver) side works perfectly.

At first, I've taken down & checked motors & cables in the mirror with tester, nothing seemed bad.

Then I've checked cables on the connector.

Only 3 cables out of 5 are used, maybe other 2 are prepared for side blinker.


Brown - ground
Red - Positive : 12V - always on
Blue - Positive : 2V - a few days later, this showed 0V

Tested other side mirror connector;

Brown - ground
Red - Positive : 12V - always on
Blue - Positive : 10V - it goes down to 7-8V when pushed mirror controller.

It looks like the controller uses the middle cable to trigger the logic board in the mirror.

Connected the mirror to the right side connector to check if the mirror was all right.

Not worked at the first time, but ridiculously it worked when the select button moved to left side. Wow. it's funny isn't it?

Okay anyways, the mirror is all good.

Y branched from the working connector to see if both of mirrors work, nice working. - It's for the last scenario in case to fail to find out the location of disconnection, I would line an additional cable from this door to other door.

Opened the door trim to see the cabling inside, but nothing bad.

Unscrewed the cover to check the connector on the body side between door hinges.


Finally heavily rusted connector revealed.


Pin 4 (blue cable) broken.



Cut the pin with 1 cm of cable from Pin7 which seemed for side winkers, don't think I would retrofit side winkers in the future, and soldered to the blue cable.

Don't forget to clean the rust with WD40 and apply some grease to prevent further water damage.

All done after a long time struggling with the mirrors.

[DavesZed]

Nice write-up there, very informative especially with our cars getting older now this sort of thing will start to happen more often.

The "rust" in this instance has a specific name, it's called "verdigris" - There you go, every day is a learning day

[Jowenkim]

Thanks a lot Dave!
I have used 'rust' on all sort of oxidation without any thought.
True! Everyday is a learning day! Verdigris

[Bail44]

My passenger (left) side mirror stopped folding...I followed your advice and found exactly the same fault - Pin 4 was broken due to verdigris due to the ingress of damp
I ordered a new pin with cable from BMW on-line, cut the old pin off, soldered on the new one with the cable already crimped on .......and all’s good
Your post was much appreciated

[cuddapah]

My Z4's passenger side exterior mirror works intermittently. Can you post instructions for removing the mirror, motor and cables. Appreciate your help.

Originally Posted by Jowenkim

Hi all,
If any one has a problem with wing mirrors, hope it helps.

[engine killer]

my driver side (rhs) mirror stopped folding for quite some time, just checked the connectors and they are very clean no verdigris at all. so i guess the motor is gone

[cuddapah]

Originally Posted by engine killer

my driver side (rhs) mirror stopped folding for quite some time, just checked the connectors and they are very clean no verdigris at all. so i guess the motor is gone

Motor in my Z4 is working. I think some gears or some other parts may have worn out. Looking for instructions to disasseble the mirror.

[Jowenkim]

Originally Posted by Bail44

My passenger (left) side mirror stopped folding...I followed your advice and found exactly the same fault - Pin 4 was broken due to verdigris due to the ingress of damp
I ordered a new pin with cable from BMW on-line, cut the old pin off, soldered on the new one with the cable already crimped on .......and all’s good
Your post was much appreciated

I've just found your comment, today I came back to this thread to send this link to someone who has same problem. I'm really happy to make someone happy with my experience.