CL500 W215 trunk not functioning

[Gordywalker]

Hi Eveybody,

I have spent days of research trying to get to the bottom of my trunk not going up and down, but just about gave in tonight and stopped.

the boot itself has never worked under my ownership.

I removed the battery and revealed a very corroded Hydraulic pump, my first thoughts was that this must be the problem so removed the pump but left the hydraulic lines connected to the rod.

I called up my local breakers yard, sent them a photo, they only had an S430 hydraulic pump available, identical to the current one but has different part numbers.

I installed the unit using my old hydraulic lines and there was plenty of hydraulic fluid in the new pump.

put it all back together but still no joy.

from my research I was told to try the related fuses under the rear seat and the engine compartment all are fine.

I tired to synchronize the boot using a method I read about on this forum but to no avail...

I then disassembled the boot locking mechanism and had a look at the so called “puck” to check for leaks or damage but it was solid.
You can hear air coming from that area where the hose is connected and feeds the puck.
Anyway with no obvious problem i reinstalled that.

then I checked the PSE unit, it had a couple of the hoses missing (2 in total) but again I read thats normal for a CL as only 2 doors.

so I am at a real loss with trying to diagnose whats wrong with it.

if anyone had anything similar and found a solution it would be great to hear from you.

thanks for reading.

 

[whitenemesis]

Broken control wire(s) in the boot hinge bellows?

 

[Gordywalker]

Yes possibly, I was thinking to try and check the wiring as it seems to be the last port of call.

 

[whitenemesis]

Have you had the codes read using STAR? Would be my first step.

 

[Gordywalker]

Haven’t had the codes read was trying to avoid the expenses of taking it to garage.

well thats a good solid 3 days I have spent trying to figure out what is wrong. Multiple trips to the breakers yard.

still no further forward so I will book it in at a garage.

i cut the black casing on the retractable wiring loom to check for any cuts but all looks in one piece.

today went to Mercedes and bough 2 new relays that are placed near the hydraulic pump but still no joy.