Boot loom / actuator

[bonbon]

My central locking closes doors but not the boot. Interestingly, my boot key locks and opens the boot and the doors.
My guess is it’s the wire in the boot loom that activates the boot lock.
If this makes sense, can anyone tell me what is the colour of that wire that can save me checking the continuity of all the wires on the loom.
Cheers

 

[John_B]

I'm sorry, I don't recall the colour, however there is a small access panel on the inside of the boot lid, pop that out and you'll see the connector for the lock actuator and that will tell you which ones to focus on.

 

[bonbon]

Based on an earlier post by Brian H, perhaps based on what I described, somebody can narrow it down to which one:
“The three wires below are supply wires and lock position wires, the supply is fed from fuse 7 (5amp)

• 0.35 RT/GN red/green - boot lock switch - supply wire
• 0.5 WS/BL white/blue - boot lock switch - unlock wire
• 0.5 WS/GN/GE white/green/yellow - boot lock switch - lock wire”

 

[Rudyrov]

I have the same issue in my Z, Is there a common place this wire tends to fail?
Thanks

 

[bonbon]

Based on the pics in this this thread - it's a White/Blue or Blue Grey (one pic appears to me from my car in 2013 as duplicated below)
It seems to happen at the bend inside the loom where the clip supports the loom (between the body and the lid).
As I rarely go into the boot, I’m tempted to just live with it until another wire gives way….

Central Locking Query

Looking at small items left on my to-do list for my Z3 1.9 and pondering this one with the central locking. If I lock/unlock the car with the key from the drivers or passengers door, both doors lock and unlock. However, this does not unlock or lock the boot. If I lock/unlock the boot with the...

zroadster.org

 

[Brian H]

I’d be inclined to think you have a faulty boot central locking actuator unit in the boot, by manually turning the key in the boot lock you are successfully triggering the signal wires to lock/unlock the car doors, as this works it would indicate to me your wiring is intact.

I’d need to dig out the wiring diagrams again to check the colours above, it’s been a minute or two since I’ve checked these.

 

[t-tony]

Makes sense to me Brian.

Tony.

 

[bonbon]

Brian, thanks for your insight.
But look at link above. I seem to have the exact same symptoms as Richardix - and he had a torn blue wire.
Am I missing something?
Also based on the following thread - it seems that most likely it is another case of loom gloom.

Z3 Trunk central lock problem

Bimmerforums is the preferred online BMW Forum and community for BMW owners. At Bimmerforums, you will find technical how-to information maintenance specifics audio advice wheel and tire combinations and model specific details not found anywhere else. Our professionals are here to help make...

www.bimmerforums.com

When I have a chance I can check the continuity of the relevant wires.
But hey - this is crazy.
Seems I did it 11 years ago 🫣 then it was Blue/Gray wire…
Recovered pics from years ago (not in order)

Boot lock / Boot Loom fix - step by step - zroadster.net

 

[Brian H]

The images are for a 1998 Z3, hope I got this correct.

So we have a 5 wire circuit, the 0.5 WS/BL and 0.5 WS/GN/GE are the signal wires to the ZKE control unit, I believe these are good as the system recognises the lock/unlock function when you manually turning the key in the boot.

As you do not get the lock or unlock function I would first test the 12vdc supply at the boot lock actuator unit (via fuse 7), we know the fuse is good as it serves the other locks but this could be a dodgy/broken wire. If you have good power then this leaves the 1.5mm motor control wires or the motor itself.

I believe the motor control wires are momentary switched negative outputs from the ZKE (not verified but it’s the only way I can see this working) so you could try grounding pins 1 & 2 (one at a time and at your own risk) to see if the motor moves.

If you are going to test as above, disconnect the plug from the actuator so you don’t fry anything else in the car

 

[bonbon]

According to the diagram - what would be the effect of Blue/Gray being severed?

 

[Brian H]

According to the diagram - what would be the effect of Blue/Gray being severed?

this is a motor signal wire to tell the motor to lock

 

[John_B]

If you want my 2 cents, I'd suggest just chopping the section out and using a repair kit on the entire thing. If one (or more) wires are already damaged, it is only a matter of time before more follow.

I have done it on two Z3s now (once preventetive, and on the other because I replaced the bootlid, and even though they were working, they were a real rats nest under all the tape and deteriorating rubbers. It's a pretty straight forward job, I used the heat-shrink + solder connectors, so didn't even need to do any soldering either.

This is the kit I purchased

Boot Wiring Loom Plug FOR Z3 1.8 1.9 2.0 2.2 2.8 3.0 3.2 CHOICE2/2 Roadster M | eBay

Multiple choices exist for:BMW Z3 1.8,1.9,2.0,2.2,2.8,3.0,3.2. FOR BMW Z3. Cable Length [mm]:490.

www.ebay.co.uk

(And these are the solder connectors

https://www.amazon.co.uk/gp/product/B0CWGCB6QW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

)

 

[bonbon]

All my 8 wires in loom have connectivity and 9 fingers ok
Is there a straightforward way to test the actuator before I order another?

 

[bonbon]

Have a great weekend

 

[bonbon]

The plot thickens - I’m not getting a 12v pulse to the actuator connector when I activate the locks.

 

[bonbon]

Not so thick….
Tested: sticking pins in the blue/gray and white wires and looking for 12V pulse while activating locks.
Before loom: 12V ok
Blue/gray before and white after loom: 12V ok
Blue/gray after loom and white after loom: No 12V
Bottom line: it’s the blue/gray in the loom again. 11 years ago I gave it 5 years
It appears that while I found some continuity in the blue/gray - it is very high resistance and cannot transfer the required current.
I was planning to repeat fix again after I have a spare loom in hand as recommended in a post above - but it is out of stock for now.
BTW - why does the replacement loom for sale have more wires than I have going into the boot lid?

 

[Dxbolton]

Not so thick….
Tested: sticking pins in the blue/gray and white wires and looking for 12V pulse while activating locks.
Before loom: 12V ok
Blue/gray before and white after loom: 12V ok
Blue/gray after loom and white after loom: No 12V
Bottom line: it’s the blue/gray in the loom again. 11 years ago I gave it 5 years
It appears that while I found some continuity in the blue/gray - it is very high resistance and cannot transfer the required current.
I was planning to repeat fix again after I have a spare loom in hand as recommended in a post above - but it is out of stock for now.
BTW - why does the replacement loom for sale have more wires than I have going into the boot lid?

It’s probably a generic loom that fits other cars too

 

[Stevo7682]

Watch this thread with interest to see outcome as my 2 pre 98 zeds dont open the boot from remote ( one of which is an absolutely immaculate one owner 36k car ) but my 99 pre face-lift and face-lift model both do.

Stephen.

 

[bonbon]

Ok - as expected - was the blue/gray again. I was able to peel back the outer sheath (I heated it up with a blow dryer) without damaging it. Replaced the splice I did 11 years ago.
It seems the manufacture of that wire was problematic. I also removed the inner black sheath as it is now very rigid and could be the cause of the problem (perhaps it was soft 28 years ago).
Pics below (not in order) similar to 11 years ago. The last pic is what I found when I opened up. (Tip - it is clear that this time the break was at the edge of the last solder fix. Next time it happens I will replace a section of the gray/blue wire such that the the two soldered joins are outside the loom)
Took only an hour (after establishing earlier that the problem appeared to be the blue/gray in the loom)

 

[John_B]

BTW - why does the replacement loom for sale have more wires than I have going into the boot lid?

It sounds as though you have resolved it, so this is no longer relevant - however just to close the loop on this, the loom repair I recommended (post #12) has the correct number of wires - 9 - for both pre-facelift Z3s I used them on - Does your car have fewer? Maybe it is a spec/year variation?