chorney

Hey guys, just got a 2005 s500. There are many issues with trunk. The first one being that the trunk will not automatically close. when I push button to close, it makes a sound but does not move. I have to push down hard manually. The soft close function works when I manually close it though. that leads me to my next problem, it only opens from the key, as shown in the video, it does not open with the buttons on the trunk, or inside the trunk. The last issue is that on the right side, towards the rear window, when I close the trunk, it sticks up (as shown in video). I have to push it down and it is level with the other side. This all could be one big problem but I think otherwise, scnince it opens with the key. Any help would be appreciated.

tusabes

Very common issue for the right corner of trunk not to seat fully , Edmund’s noted this in their December 15 long term report
https://www.edmunds.com/mercedes-ben...gned-trunk-lid


it’s also very common for the trunk buttons to not work, that’s because the wiring from inside the trunk to the trunk lid is encase in a retractable coil that gets severed. The coil is located where the trunk cable goes from the lid into the trunk. So that’s the problem why your trunk buttons inside and outside the trunk are not working.


Also, for the reason why the corner of the trunk is not closing properly, you likely have a combination of 3 problems - weak gas trunk struts , low fluid in the hyraulic trunk lifter , bad pse pump for the trunk latch . Do the first two and see if that fixes it . The gas struts are simple to access and cheap on eBay or Amazon . The hydraulic trunk lifter is encased in foam under the battery and you can add ATF in its fluid reservoir

chorney

Thank you, I will try to fix all of this tomorrow morning. I will post here my findings.

chorney

Also, can you please explain more or provide a picture or video of where the severed coil would be?

wallyp

Congratulations - I think that you will greatly enjoy the car, especially as you appear to have the required mind-set to be willing to learn how to take care of problems.

For the high corner: Use a good penetrating oil, such as Kroil (but not WD-40) on every joint in the trunk hinges every day for two or three days.

For the non-functional PSE operations, look behind the right rear passenger's heels and find the floor lamp. Pull it out of the carpeted wall, but don't bother to disconnect it. Find the yellow 20-Amp fuse toward the right end of the row, pull it out and see if it is blown. Replace it, reinstall the lamp, and see if the trunk functions now work. You have just reset the PSE (Pneumatic Service Equipment) Control Module.

For the possible broken wire, look in the forward right corner of the trunk, and find the cloth-covered wire harness running from the body to the trunk lid. That harness winds out and back on a spring-powered drum as the lid moves. It is common for a wire or two to break due to the flexing.

chorney

Thank you for the suggestions, I am trying these today, Its my first car and I am on spring break, so I have much time to tackle these problems.

chorney

Hey guys, there is plenty of fluid in the pump. I checked the wiring and didnt see any severed wires. I dont really know what i am looking for though. Im not sure what the next step would be. any help appreciated

wallyp

Do everything thing that has ALREADY been suggested FIRST!


IF the problem is a broken wire in the trunk harness, there will not be a severed wire. There will be a wire buried inside a wire harness that has broken inside the insulation, but still looks perfect.

IF this is the problem, repairing it will not be fun, but will be a real learning experience.

IF this is the problem, your choices appear to be:
- Learn to do the repair yourself. Hours of research, hours of fiddley work. Virtually no cost, and a great feeling of satisfaction after you successfully do the repair.
- Pay someone else hundreds and hundreds of dollars to do the repair.
- Live with it.

Look carefully at the third photo. On the top edge, above the yellow wire, you will see what looks like a black U-shape plastic piece. Inside that piece is a cloth-covered wire harness. That is the harness for the wires on the trunk lid, and is the harness that winds in and out on a spring-loaded spool. It is not unusual for one of the several wires inside that harness to fail from metal fatigue due to years of flexing. That may not be your problem in this case!

One approach is to find where the wires disappear into the harness near the spring-loaded reel. Pick out a wire using the color code of the wire. Go to the wires in the first photo and find the same color code - the same wire. Use two fine straight pins and a multimeter to check for continuity on the wire. If/when you find the broken wire, you get to take the harness and reel out of the car, dig down into the harness and find the broken spot, and repair it

Again, check everything else first, starting with resetting the PSE Control Module, then checking for a failed pneumatic actuator.

tusabes

It is much easier just to get a used coil wire harness from a junkyard car and swap it out

kraut56

One way to get things under control is to :re-initialize" the trunk system using Xentry/SDS.
Has this been done?