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Great thread, thanks to all those who contributed!
My issue is a little different. 03 E500, automatic trunk closer does not function. The trunk will open an inch then I have to force it open, to close I have to force it close until it strikes the locking latch and that motor pulls it closed and locks. The high mount brake light, license plate lights, interior trunk lights and red trunk close button are all working. I examined wiring and found that the wires had been repaired once before and examined the repairs under the electrical tape and everything looks fine. When I press the trunk close button I hear a click sound from the electronic module by the gears but no sound from that motor attached to the gears. Could I have a bad motor? I keep going back to the wires trying to find a flaw in one of the wires but can't find anything that hasn't already been dealt with. Does anyone have any suggestions? Thank you!!!
Great thread, thanks to all those who contributed!
My issue is a little different. 03 E500, automatic trunk closer does not function. The trunk will open an inch then I have to force it open, to close I have to force it close until it strikes the locking latch and that motor pulls it closed and locks. The high mount brake light, license plate lights, interior trunk lights and red trunk close button are all working. I examined wiring and found that the wires had been repaired once before and examined the repairs under the electrical tape and everything looks fine. When I press the trunk close button I hear a click sound from the electronic module by the gears but no sound from that motor attached to the gears. Could I have a bad motor? I keep going back to the wires trying to find a flaw in one of the wires but can't find anything that hasn't already been dealt with. Does anyone have any suggestions? Thank you!!!
Bad motor, bad sensor on the gear, bad controller, or one or more of the switches in the upper or lower latch part is bad.
OR . . . .
You can do like me, and test every part you can, (all but the controller), then decide it had to be the controller and buy one off ebay, then put it all back together and have it still not work, then swap the old controller in and all of a sudden it starts working.
Anyone want a spare controller module?
Does anyone happen to have a diagram which identifies all of these related parts that N_Jay mentioned?
Also, does anyone have a diagram of what each of the wires in the harness controls?
Thanks!
Thanks N_Jay
I took a second look at all of the wiring and aside from the fact that some of the wire sheaths are frayed the copper is still strong and connected so I can be reasonably certain it is not the harness. When I press the red illuminated close button I hear a click from near the motor which I assume is that electronic module trying to communicate with the motor but of course no response from the motor. Does it make sense to assume that it must be the motor assembly that is at fault (2118202042)? Is there any way to test the motor specifically prior to removing it and buying one from a wrecker?
The motor is a 12volt motor, and if you have a few alligator clips you can make it run and check.
the sensor is a variable resistor, so you can look at that also.
The latches have switches, do you can test those also.
Now I’m really confused!
Got the motor out, connected it to the battery and it runs like a charm! It seems to work perfectly rotating the gear in either direction. I’m thinking with a small electric motor like this it either works or it doesn’t right?
Next I reconnected all the wiring, all except the final plug going into the motor and when the trunk close button is pressed I get power coming to the plug that would normally be plugged into the motor. Is this exact voltage critical?
On a side note when the motor is completely installed and connected but with the arm to the trunk hinge disconnected, press the button and the arm moves about .125”. It is as if with no resistance from the trunk springs the motor is trying to spin.
Hope this all makes sense! Thank you!!
N_Jay,
When you say the sensor is a variable resistor I’m assuming you are referring to the potentiometer sensor with the white plastic arm attached (2118201597)? How would I test that?
Also could it be the Trunk Control Module (2118703026)?
Thank you!!!
N_Jay,
When you say the sensor is a variable resistor I’m assuming you are referring to the potentiometer sensor with the white plastic arm attached (2118201597)? How would I test that?
Also could it be the Trunk Control Module (2118703026)?
Thank you!!!
You have to put an ohm meter across the pins and move it.
I did not remove my motor to test (and hit my head with the trunk lid)
It "could" be the controller, hence the fact I have an extra.
As I said, there are switches in the latches that with some careful work can be tested with an ohmmeter.
There is also a motor in the lower latch, but it sounds like that is working in your case.
I never did find out what was wrong with mine, but when in failure mode the trunk close button was not lit, and when working fine was lit.
I think using the escape button seemed to be part of what got it all back in sync and working.
Thanks for all your support N_Jay!
I am working on my moms 03 E500 but I also have a 2005 E55 with auto trunk closer. In the process of trying to test the the various components of course I broke a plastic part on the potentiometer. So I said F it and took the same part off my E55 and tried it on the E500, no luck. Then I decided it was easy enough to swap out the control unit so I put that on the E500 and voila it seems to work!!!
Now, the trunk will only open half way!!! I tried resetting it per manual instructions by pressing and holding the red button longer than 5 seconds but that doesn’t work. I’ve tried it dozens of times in subtle different ways but still only opens half way. On the 03 this cannot be changed by way of the steering wheel controls and menus in the instrument cluster. My mom took the car to our trusty indy Mercedes guy and he reset the system several times on his computer but still no luck. I’ve now read dozens of threads on this subject of the trunk only closing part way and I feel like I have tried everything!! It’s my understanding that all of these parts are fully cross compatible.
Please help me finally finish this ridiculous project!!!
Wife came back from the grocery store, unloaded groceries from the trunk and went inside. Shortly after that she heard the sound of the trunk opening itself in the garage. I came home to find both taillights and the third brake light flickering. Sounds like the wiring harness to me. I will take a look tomorrow. I opened and closed the trunk a few times and got the lights to cut off, so I am pretty confident as to the problem (I hope those are not famous last words!).
I thought the trunk opening itself was pretty sporty, though.
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.
Hi Everyone,
I wanted to say thank you to hbamark and everyone else who added and shared the solution (e.g. description, steps, and photos) to the existing problem.
Two days ago, I experienced the exact same problem after putting my groceries into the trunk and closing it. I strongly believe that the freezing temperatures (-19 C) with the killing windchill (-25 C = -13 F) added to the inevitable problem.
I turned for help in this forum. I quickly found the solution here.
I allowed myself to throw in one photo of the past and bad memory for your review guys.
Then, I applied the solution. It is all working now!
Nine years later and still saving the day! Thanks hbamark. An intermittent problem on 2009 e350 for the last year until it finally quit entirely. Trunk release, trunk light, and license plate light. I read your post and went right to the break. Brown wire just held together by the insulation so it would work and then go open. I never would have found this it was so hard to see. I was ready to bite the bullet and go to the dealer, but with this post I found it in 20 minutes. Thanks to everybody who contribute to this site
Thank you all - trunk 3rd brake light and number plate lamp issue - removed panel and found that brown cable was severed - used a butt splice and re cable tied hoping that the cable tie distant aggravate the issues
Used a bit of solder on each end and a \"blue" butt splice Hey presto - thanks
Cable was broken where the cable tie was binding the loom to the hinge
Found this post and found the problem ... brown wire broken at the pinch point where the tie wrap secured the plastic wire loom to the trunk lid left arm.
Easy and no cost fix because of this thread.
Mahalo nui loa.
Last edited by eaglehawaii; Apr 23, 2018 at 05:58 PM.
Reason: added add'l info to clarify my post
wow !!!
no center brake light, power trunk release or license plate lights
brown wire cut, took 5 mins to fix, great tip!
never believe in coincidences, right?
Same problem, same fix. It seemed like either a piece of the brown wire was missing, or it was shorter than the rest of the wires in the harness. I added a couple inches of wire, soldered both ends, shrink wrapped and BOOM! Everything works again.
Thanks from 10 yrs after your initial post.
M@
Thank you for this post. However Come on Mercedes-Benz seriously it’s been a common problem for E-class owners for how manny years? And there is no recall.... that’s pretty bad for such a quality brand I experienced this issue slowly with the interior trunk lights not working. Then the license plate trunk lights went out sometimes when trunk opening and closing. Another trunk has stopped working completely and all those three warning lights are on. Also the easy access lock and unlock button stopped working on the rear passenger door handle drivers side. I’m wondering if that is also tied in with this crap. Unbelievable Mercedes-Benz. Why would they put wiring in a place where it involves lots of movement.... Mercedes Benz should take full responsibility. Hey guys is there a permanent fix to this or will there always be this issue? I’m seriously pissed.
Last edited by Oliboro100; Apr 27, 2019 at 02:41 PM.
Thank you for this post. However Come on Mercedes-Benz seriously it’s been a common problem for E-class owners for how manny years? And there is no recall.... that’s pretty bad for such a quality brand I experienced this issue slowly with the interior trunk lights not working. Then the license plate trunk lights went out sometimes when trunk opening and closing. Another trunk has stopped working completely and all those three warning lights are on. Also the easy access lock and unlock button stopped working on the rear passenger door handle drivers side. I’m wondering if that is also tied in with this crap. Unbelievable Mercedes-Benz. Why would they put wiring in a place where it involves lots of movement.... Mercedes Benz should take full responsibility. Hey guys is there a permanent fix to this or will there always be this issue? I’m seriously pissed.
Chill!
The trunk issue is completely separate from the door issue.
The door latch issue is the rubber seal behind the button breaking letting water into the switch assembly. Yes they should probably last longer than they do.
The trunk is the wire where the hinge bends when the trunk opens the wire has to bend The only thing they could do is make sliding contacts or a loop of wire either of those create other issues.
Just remember, every product is a compromise.
How many miles did your car go before the trunk showed up as a problem, how many times was it open and closed?
Nothing lasts forever.
Thank you everyone in this post especially hbamark!!! Exactly as you all have described. Took a few minutes to find the broken wire, but it was right about where you suggested and it was the brown one. Terrible design flaw MB.
Sorry to zombie up this thread, but this was so great. Read the initial post, fixed it in the parking lot at work. Its for an E Class, but I am sure you all know a CLS is just a swoopier E Class.
I just fixed this on my 2008 E350 4matic keyless go. There are two reasons that the brown wire is the most likely one to break first. 1. That wire is a common return ground for all the circuits, therefore it is thicker and stiffer than the smaller supply wires adjacent to it. MB chose to use a very stiff wire type for this that is less able to handle the repeated bending stress. The smaller wires are more flexible. 2. The bending forces are concentrated over a very short length due to a bad design. The large plastic cover over the arm ends right where the flexible plastic wire shield starts. That flexible corrugated wire cover should have extended farther under the plastic arm cover. MB's design allows the wire bundle to flex far too much at that stress point. When the trunk opens and closes all the wire bending is concentrated at that spot instead of being spread out over a longer length of the wires. I did two things to address this. First, I spliced in a short extra length of flexible multi strand copper wire to create a more resilient joint. Second I added another loose wire tie around the corrugated wire bundle cover at the point where the trunk gear bracket and spring attach to the arm. This prevents all the bending from happening at the point where the wires leave the plastic plastic arm cover. I left this tie loose so the wire bundle could slide and not create a new sharp bending point . This will spread out the bending arc of the wires over a longer distance. Understanding the cause of a problem helps engineer a longer term fix.
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.[/QUO
i have no power to any rear lights or trunk release can’t find any broken wires
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Jun 12, 2015, 07:03 PM
Fantastic instructions
3rd brake lamp, license plate lamp left, right, internal trunk lights & trunk locked
