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S500 trunk self closing/opening issue

3K views 5 replies 4 participants last post by  constant.p 
#1 ·
I just bought a used 01 S500 without any extended warranty. Recently, the automatic trunk open/close system no longer works from either the remote, the trunk button on the door (red led no longer on), or the red trunk button. Pressing either the door trunk or remote just unlocks the trunk without any movement up or down. BTW i have tried holding the buttons for 5 seconds. i have already check/remove/reinstall all the fuses which are 13, 57 and 62 (which i know by heart now) and they are fine. The door/trunk close assist (pulling the lid/door in tightly) still work fine for the trunk and the other 4 doors.

Please help before I have to resort to the stealership.
 
#2 ·
I had a similar problem with a 2004 while using the valet key the system later was non functional with the hydraulics, however the red closing light did work. I had to play with the valet key a couple of times before the auto trunk closing came on-line. Some models “setup” in the instrument panel allow you to modify or disengage this feature, check and see, and maybe reset to factory specs.
Hope this helps, also could the hydraulic lifters need replacement?

REMI
 
#4 ·
I think that this issue electrical, as in there is no voltage going to the trunk closing mechanism. THe soft closing system for all 4 doors and trunk still work. THe LED in the trunk button (in driver door) stays off.

THe trunk self opens and closes via an hydraulic pump located right next to the battery. THe pump sends fluid to a strut located right above it (behind the liner) to raise and lower the lid, very similar to a dump truck hydraulic system.

Next I plan to operate the pump directly with the battery which would confirm that the pump is working. Then it's question of figuring out why there is no power going to the pump.
 
#6 · (Edited)
S 500 loked trunk

Now the path is this. button on the door, SAM, 2 wire CAN ( here is DATA) , CAN module in the trunk, electric air valve, air actuator, lever, pop open. Do you hear two hissses... when you press the button on the door?? Do not even think about making a hole in the key lock and pick the lock. Does not work. You have to reach the lever which pops the fork. ( just a hole and a wire).
 
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