Hi All - I wonder if anyone here may be able to shed some light on the boot release issues I have with my 2005 CL500. I have done some preliminary investigation, but I need a little bit of insight to take it further - hoping someone on here can help.

From what I see there are 2 main mechanisms that open the boot - both are not working on my car at the moment.

Air Release/Actuator system:
The main one that most people know about is the air pressure/actuator system. On my car thats currently not working because the air tube within the wiring loom has kinked and actually now fully snapped so the air doesn't make it to the actuator to release the lock (see attached photo). I can see where its broken and its quite easy to access, but I don't know if its possible to repair the air tube without having to simply replace the entire wiring loom. Does anyone know if thats possible at all? For some context - this air mechanism stopped failing a while ago when the tube was kinked but not fully broken. I was able to patch-fix it by wrapping tape around it and that worked fine for many months - but now the tube has completely snapped.

Snapped air tube - can this be repaired?


Button Release Mechanism
The button release mechanism on my car also is not working .... that is apart from the emergency method where I use the key in the boot button and twist/press to open the boot - that still works fine and thats my only way to access the boot at the moment.
See photo attached - the button arm (circled red) moves back and forward ok when the button is pressed, but its position misses the door unlock arm (circled in blue). Its as if when you unlock the boot the red circled arm should twist into place so when the button is pressed it engages with the release arm and opens the lock. When I use the emergency mechanism with the key, the red circled arm turns into place and allows me to open the door, so I suspect something is wrong with the central locking system where it doesnt turn the arm into place when opened (ie central locking is not activating the boot mechanism properly).

Is there a fuse or a relay somewhere that might be defective that activates the boot lock when central locking is opened? All other electrics to the rear seem to work fine (lights interior and plate lights, and central brake light strip all work ok).
The other thing I have noticed that may well be significant is that the soft close mechanism to the boot has also stopped working but that may be related to the air system/tube above (soft close on the doors still works fine).


Boot button mechanism

 

Just a quick update on this.

For the air system, I have actually managed to do a quick fix for now, but I intend to try and do a better in-place fix based on a post I managed to find on another forum.

The quick fix I did for now is that I actually had some shrink-fit sleeves for wires lying around. I slid one over the nylon piping and used that to temporarily join the ends together - using a heat gun (with as little heat as possible to avoid melting the existing lines) to shrink the sleeves in place.

I have since found out that the tubing is 4mm nylon and an alternative fix is to buy some 5mm nylon tubing (slightly wider) and use a section of the 5mm tubing to join and extend the 2 broken sides together using glue. I'll give that a try when I get a chance.

Still none the wiser as to why the central locking mechanism isn't enabling the trunk release to work, but its less of an issue now that I can open the boot with the key fob and also with the release button inside the car.

 

Also ... it appears that the soft-close for the trunk is not working because once the air pressure system stops working, the PSE system shuts off that line of pneumatic pressure to protect the pump itself. I think I just need to reset it either by pulling the fuse for the PSE, or maybe I can reset it with my ODBC scanner.

 

Ok - further update to my thread. All issues fixed!!

For the air tubing, I fixed it as described above - using a slightly wider nylon tube (6mm OD x 4mm ID) to go around the break in the original tubing at both ends. I then used shrink wrap AND also some electrical tape to secure the new tubing in place.

The soft-close was fixed by resetting the PSE pump by briefly removing and replacing the PSE fuse to reset that system once the air tubing issue was resolved. It seems that if the air system is failing, the pump has a self protection mechanism and disables itself to protect the motor - it needs a reset to get going again.

For the button unlock issue - I discovered whilst fixing the first issue that further down in the wiring loom one of the wires had broken, so I fixed that using about 1 inch of an additional wire and used shrink wrap to secure it in place. That was the source of the button press issue, so now everything is working perfectly.

Hopefully someone will find this useful in the future.