- Mercedes-Benz E-Class: How to Repair Power to the Trunk
Step by step instructions for do-it-yourself repairs
No power to trunk, 3rd brake light, or license plate lamps
I wrapped the entire section of wire in the area of the repair with electrical tape. Then, I reattached to the swing arm with a zip tie. However, I left some slack in the zip tie so the wires can move freely without getting severed again.
Now, I must repair two other issues. 1) The Brake/Stop Light Switch issue and 2) I have received the temperature stop car immediately message twice in the past week.
Last edited by mbnnrh; Apr 29, 2014 at 01:00 AM.




We are away on vacation and almost had golf clubs locked in the trunk.
This is the first time I needed to use the trunk key and of course set of the alarm.
Hopefully it is the simple fix like everyone else.
Last edited by N_Jay; Jun 24, 2014 at 11:31 PM.




I had trouble figuring out all the pieces that need to come out to loosen the side panel. There was even one bolt.
I used a butt connector, covered it with heat shrink, then wrapped that bundle about 2 inches in and out of the loom.
Then started past the loom and wrapped the outside to keep the loom end from moving.
Don't go crazy as it still has to fit under the hinge cover.
The Best of Mercedes & AMG
Then I googled "3rd brake lamp" and found the posts on this forum. It was exactly what was described - for some strange reason, the brown wire which is part of a bundle of wires attached to the left hinge of the trunk with a plastic tie was "cut". I don't know how, but suspect the black plastic part which covers the left hinge hits the wire as the trunk is opened and closed and over time, it's like bending a piece of wire up and down repeatedly until it breaks.
The way I repaired mine was strip both ends of the brown wire about 3/8", twist them together and solder them. Then just use electrical tape to protect the connection. I cut the plastic tie which supported the wire bundle. Next I used a black 3/8" plastic split loom and wrapped it around the entire wire bundle and secured the wires with a new plastic tie.
Notes:
1. When you remove the left panel cover inside the trunk, you will have to remove 2 plastic fasteners on the side and 2 fasteners on the bottom.
2. I found that I had to remove the plastic panel on the rear as well to make it easier to remove the left panel. There are 6 plastic fasteners to remove.
3. All fasteners were reusable.
4. When you reconnect the brown wire, the car will start honking the alarm. Relax, just use your key to turn it off.
5. Test the car before putting everything back. On mine, it still displayed the error message. I popped the trunk and restarted the car and that somehow reset it.
6. On mine the brown wire severed INSIDE the plastic piece which covered the hinge. I had to remove the plastic piece to get at the brown wire.
If your vehicle has lost power to the trunk unit, and lights, there is a very simple fix. This is fairly common problem on W211 models. The wires get caught it trunk hardware and get severed. The dealer wanted to charge me $250 for something that took me 20 minutes and less that $10 to complete. Here's what I did.
1. Use the key to manually open the trunk.
2. Remove two plastic pins holding carpet/panel on the driver side of trunk. Pull carpet/panel away carefully.
3. Remove plastic cover on left trunk hinge by unfastening pin at top of cover.
4. Follow the wires until you find where they are severed.
5. Strip wires slightly.
6. Put a piece of shrink tubing over one side of the wires.
7. twist severed wires back together where you stripped and exposed the copper.
8. Solder the wires.
9. Pull the shrink tubing down over the exposed copper.
10. Heat the tubing so that it shrinks around the exposed wire.
11. rewrap wire so that it follows the left hinge in a manner that is will not get cut again. (I wrapped the at risk area in duct tape, not pretty, but it was effective).
12. Reinstall Panels.
Sorry for the lack of pictures, but this is a real easy fix. I hope this procedure saves some $$$ for someone.
I had by chance just purchased a set of both heat shrink wrapping and butt connectors, so I was well equipped to fix.

15 minutes later, all is well. Definitely seems to be a common issue with W211's.
Cheers.
Brown wire, down where the plastic tubing finished. Figured out the fixing OK just life the centre tab and they come out very easily.
Thanks again




They probably should have also used a thinner stranded more flexible type of wire.

If your vehicle has lost power to the trunk unit, and lights, there is a very simple fix. This is fairly common problem on W211 models. The wires get caught it trunk hardware and get severed. The dealer wanted to charge me $250 for something that took me 20 minutes and less that $10 to complete. Here's what I did.
1. Use the key to manually open the trunk.
2. Remove two plastic pins holding carpet/panel on the driver side of trunk. Pull carpet/panel away carefully.
3. Remove plastic cover on left trunk hinge by unfastening pin at top of cover.
4. Follow the wires until you find where they are severed.
5. Strip wires slightly.
6. Put a piece of shrink tubing over one side of the wires.
7. twist severed wires back together where you stripped and exposed the copper.
8. Solder the wires.
9. Pull the shrink tubing down over the exposed copper.
10. Heat the tubing so that it shrinks around the exposed wire.
11. rewrap wire so that it follows the left hinge in a manner that is will not get cut again. (I wrapped the at risk area in duct tape, not pretty, but it was effective).
12. Reinstall Panels.
Sorry for the lack of pictures, but this is a real easy fix. I hope this procedure saves some $$$ for someone.
Had the same problem. Followed the instructions. Brown wire was split/broke. An easy fix with help from this post. Thank you sooooooo much!!!!!!
alan




The key is a little tricky.
I forget which way you turn it, but the trick is to;
1) TURN THE KEY ALL THE WAY.
2) HOLD THE KEY TURNED
3) PULL THE TRUNK RELEASE HANDLE
Try one way first and then the other.
My 2007 had an added tie wrap that held the bundle to the curved trunk support. Brown wire broke right where tie wrap restrained the bundle. Looks like the 'fix' was worse than the original problem. I removed tie wrap and wrapped with cloth electrical tape.






