W219 Trunk Assist
Thread Starter
Junior Member
Joined: Oct 2016
Posts: 26
Likes: 2
From: Overland Park, KS
2008 CLS 550 AMG Diamond White Edition, 2008 CLS 550, 2015 Duramax 2500 CCSB
W219 Trunk Assist
Trunk Assist stopped working - we've never heard this before. I had the dealer fix the wiring harness issue three years ago before I had a problem and I just checked the job they did back then and the harness going up the driver side arm is not the issue in this case. Third brake light is functioning and the locking mechanism is locking and unlocking just fine - the lid just doesn't go up or get pulled down. I can open/close it manually and the lock will engage, but that is all.
Anybody expereincethis exact set of circumstances? Would appreciate it if someone would share the fix if it is know.
Thanks in advance!
Anybody expereincethis exact set of circumstances? Would appreciate it if someone would share the fix if it is know.
Thanks in advance!
Senior Member
Joined: Nov 2018
Posts: 335
Likes: 54
CLS55 AMG
I just had this same issue on my w219 and ended up having to replace both the trunk assist motor and the controller. I found a used motor on amazon and a used controller on eBay to offset some of the cost. All the work was done at Eurocharged Austin.
Thread Starter
Junior Member
Joined: Oct 2016
Posts: 26
Likes: 2
From: Overland Park, KS
2008 CLS 550 AMG Diamond White Edition, 2008 CLS 550, 2015 Duramax 2500 CCSB
First of all, THANK YOU for responding. I have been amazed at the lack of community in the MB circle in contrast to my participation in the BMW and Ford/GMC diesel forums. I beleive this may be the very first response I've gotten.
That said, can you please just confirm that your latch was working properly once you manually lowered the lid and if all of the lights, including the third brake light were functioning?
That said, can you please just confirm that your latch was working properly once you manually lowered the lid and if all of the lights, including the third brake light were functioning?
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Joined: Jul 2018
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From: Greater Cleveland area
2019 Dune Silver Metallic E-450 Mercedes Cabriolet NEW Mercedes 2020 GLC300 graphite gray SUV
Checking your posts, I see you've gotten various and sundry responses to your posts and threads. So you have gotten feedback. Responses are based on the popularity of the thread and relevance. My goodness, you're a newbie in terms of posting...only 13 in 2 years....give it time!
Thread Starter
Junior Member
Joined: Oct 2016
Posts: 26
Likes: 2
From: Overland Park, KS
2008 CLS 550 AMG Diamond White Edition, 2008 CLS 550, 2015 Duramax 2500 CCSB
I think if you look at the responses, weren't all of those tied to a political thread around gun violence? I may have sites confused, but I can say there are a ton of unanswered threads here and maybe it's just because I'm picking the most uncommon, uninteresting topics to search. Now I'm curious - I'm going to do a search to see! 
Senior Member
Joined: Nov 2018
Posts: 335
Likes: 54
CLS55 AMG
The trunk close button light was working, as was the third brake light. No issuse reported with the wiring.
Thread Starter
Junior Member
Joined: Oct 2016
Posts: 26
Likes: 2
From: Overland Park, KS
2008 CLS 550 AMG Diamond White Edition, 2008 CLS 550, 2015 Duramax 2500 CCSB
Ok. This is exactly my condition. Hmm. Might take a chance on an ECM from eBay. Dealer says it could also be the motor or the position sensor. Thanks again for the feedback.
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Senior Member
Joined: Nov 2018
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CLS55 AMG
FYI here is a link to the exact part on Amazon for the trunk motor:
I paid about $165 for the motor and ~$45 or so for an eBay controller. It was around $600 in labor to get it all installed. For reference, the motor and controller from the dealer were over $900.
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Thread Starter
Junior Member
Joined: Oct 2016
Posts: 26
Likes: 2
From: Overland Park, KS
2008 CLS 550 AMG Diamond White Edition, 2008 CLS 550, 2015 Duramax 2500 CCSB
FYI here is a link to the exact part on Amazon for the trunk motor: https://www.amazon.com/gp/product/B07FP113QD/ref=ppx_od_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 I paid about $165 for the motor and ~$45 or so for an eBay controller. It was around $600 in labor to get it all installed. For reference, the motor and controller from the dealer were over $900.
Last edited by CaptainKirk2016; Feb 8, 2019 at 10:05 AM.
Senior Member
Joined: Jan 2007
Posts: 309
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From: Central Pennsylvania
1994 S420 RIP (2/8/13), 06 CLS55, 02 ML55, 94 TT Supra, 89 Maserati 228, 911 Porsche Carerra
Try the controller module first. Mine did exactly the same thing and I replaced the controller module and back in business. Did an autopsy on the “ dead” unit and there were small burn marks on the board near some of the surface mount components. Itstcooks. That and the audio gateway because they used a cheesy Chinese fan to cool it and it seizes and everything shuts down.
