Z4 E89 23i user here, but ...

[Redline]

It is not about "if", but about "when" BMW had used poor quality electrical harness in roof (the harness is made with cables that are not industrial grade for application like bending or twisting).

Not heard of any loom failures, but, then I haven't gone out looking for them. Sensor failures are common. The loom is carrying only signal cables and not lots of current, so, they don't have to be significant is size. The key issue will be wire gauge used in the stranded cables, ensuring the minimum bend radius isn't too small for the cable and that no cables are squeezed during operation.

What's the reason you state 'poor quality'?
Which part of the harness in particular is prone to failure?
I'll take a look at the cable routing when I get chance.

 

[cra3y]

Not me. I saw first cases in german forum few years ago. Now these faults (electrical cable break in critical areas - bending ones) are appearing more frequently that led some german fellows to do preemptive steps by replacing whole harness or critical parts.

About my Z4 - I'm quite happy with. It is similar to have beautiful wife/girlfriend (the car looks), which is sex god (drive quality), but she is mental (electrical gremlins and some other faults)

PS: I have posted in my first posts, why I'm here - to find more info about Z3 :- ) (the less prettier wife/girlfriend, not so good in sex like Z4, but less mental ;-)

 

[Jack Ratt]

A big belated "Hello" from me