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Rear trunk won't open
- Thread starter commasign
- Start date
beeeerock
Active Member
Weird. I just give it a sharp push, like slamming a regular trunk, when it's an inch or so from engaging. The trunk just closes and there's no noise from the motor. 2015 85D.
Gtech
Active Member
My power liftgate won't open sometimes but I have a slightly different issue. When opening it almost seems that the liftgate is already lifting while the liftgate latch is still partly or sticking in the closed position. Already tried greasing the liftgate latch but makes no difference. My theory is that when you give the 'unlatch' signal with the key or liftgate handle the liftgate cinch actuator is activated and when the liftgate latch sends the signal 'open' the power liftgate will start lifting. Think I'll start with changing out the liftgate latch assembly first.
The cinch motor on my 2016 refresh was replaced in 2019 in post #126 in this thread, but the replacement also just failed less than two months out of warranty. Mobile service wanted $450 to replace the motor and latch. I was able to get the liftgate to pop open after a few weeks of trying to "surprise" wake it from sleep; but despite putting a towel on the latch, it got stuck closed again. Worried that they might charge even more to destroy trim pieces again, I went the DIY route this time for total of $35.
Was able to get the liftgate to pop open the first try by disconnecting the power per the helpful video in this thread. Picked up the Mercedes version of the cinch motor off eBay for $35, and took about 30 minutes to replace. Reminder to self to plug the power cable back into the new motor before panicking, after doing so works fine again. Just a tip to others regarding the hatch clips that hold the plastic trim pieces to the liftgate. On the top trim, you pull down away from the glass. On the side trim pieces, you pull sideways towards the opposite side trim pieces, not down towards the floor (which tends to shear them off). Also make sure they're slid back in place, and aligned with the holes, before trying to punch them back in Not clear from the videos... I realize the clips are $1 apiece, but every car I've owned uses different clips and can be a pain to figure out what to order online..
One puzzling thing, the broken motor (rev B) made a noticeable whirring sound each time it closed. The new one makes no audible sound at all. So not sure if it's cinching or not, yet everything works fine, whether I push down on the liftgate to close firmly, or let it power close. While I didn't make any adjustment to the latch positioning, I did lower all the bumper stops to reduce any strain on the new motor.
Does it not maybe not need use the cinch motor if the latch is well-aligned?
Was able to get the liftgate to pop open the first try by disconnecting the power per the helpful video in this thread. Picked up the Mercedes version of the cinch motor off eBay for $35, and took about 30 minutes to replace. Reminder to self to plug the power cable back into the new motor before panicking, after doing so works fine again. Just a tip to others regarding the hatch clips that hold the plastic trim pieces to the liftgate. On the top trim, you pull down away from the glass. On the side trim pieces, you pull sideways towards the opposite side trim pieces, not down towards the floor (which tends to shear them off). Also make sure they're slid back in place, and aligned with the holes, before trying to punch them back in Not clear from the videos... I realize the clips are $1 apiece, but every car I've owned uses different clips and can be a pain to figure out what to order online..
One puzzling thing, the broken motor (rev B) made a noticeable whirring sound each time it closed. The new one makes no audible sound at all. So not sure if it's cinching or not, yet everything works fine, whether I push down on the liftgate to close firmly, or let it power close. While I didn't make any adjustment to the latch positioning, I did lower all the bumper stops to reduce any strain on the new motor.
Does it not maybe not need use the cinch motor if the latch is well-aligned?
Ah, that must have been it! Had a couple of doors open since I was testing with the touchscreen and accessing the actuator disconnect inside in quarter panel. Not sure why the two are related, but must be some sort of consumer safety concern...
Just tested again now and I do hear the familiar actuator whirring sound upon closing.
Thank you for this excellent thread!
We are on a short road trip in our 2015 90D S and had this issue yesterday (trunk is closed but car senses that it is open.) We were not looking forward to driving through 100F temps without AC! We have temporarily solved our problem and can use the trunk manually & have access to to all of our usual control systems thanks to you fabulous forum folks.
After doing a reset with the thumb wheels we were able to open the trunk with the manual trunk latch (we didn't have to follow the instructions on the video linked up-thread).
We noticed when we manually shut the trunk that the cinch actuator made an odd noise so we are now leaving a car door open when we close the trunk. We learned via this thread that the cinch actuator does not engage when any other door is open and we want to avoid using that part.
We bought some trim removal tools and T20 & T25 in case we needed to follow the tips on the video. We hadn't removed panels before, so as a side exploration we learned how to do that and were able to see our secondary fuse box (on our car, the lift gate fuse is F210 and is located in the front passenger footwell, exterior wall). We thought perhaps that we would pull the fuse as another user described, but are confident that we can operate our trunk manually so we won't mess with it.
Although this trunk issue is inconvenient, we are planning a much longer road trip later this year so the knowledge we now have about removing trim and accessing fuses is fabulous. When we get home we will repair our cinch actuator using this thread and YouTube. Because, why not?
Thanks, All!
We are on a short road trip in our 2015 90D S and had this issue yesterday (trunk is closed but car senses that it is open.) We were not looking forward to driving through 100F temps without AC! We have temporarily solved our problem and can use the trunk manually & have access to to all of our usual control systems thanks to you fabulous forum folks.
After doing a reset with the thumb wheels we were able to open the trunk with the manual trunk latch (we didn't have to follow the instructions on the video linked up-thread).
We noticed when we manually shut the trunk that the cinch actuator made an odd noise so we are now leaving a car door open when we close the trunk. We learned via this thread that the cinch actuator does not engage when any other door is open and we want to avoid using that part.
We bought some trim removal tools and T20 & T25 in case we needed to follow the tips on the video. We hadn't removed panels before, so as a side exploration we learned how to do that and were able to see our secondary fuse box (on our car, the lift gate fuse is F210 and is located in the front passenger footwell, exterior wall). We thought perhaps that we would pull the fuse as another user described, but are confident that we can operate our trunk manually so we won't mess with it.
Although this trunk issue is inconvenient, we are planning a much longer road trip later this year so the knowledge we now have about removing trim and accessing fuses is fabulous. When we get home we will repair our cinch actuator using this thread and YouTube. Because, why not?
Thanks, All!
...car is in SC now...Obviously this is a long term issue, especially since people are now having it fail AGAIN after being replaced.
Had this happen on a 2017 75D today. I followed the instructions in the video and removed the actuator. It seems that the only issue with not having the actuator is that the trunk does not fully close with all doors closed. I just need to manually push down the trunk. It closes all teh way if I have a door open.
Thanks Jozefr. The sellers on Ebay have applied the Tesla Tax and want $130 for used versions. I used your part number on a Mercedes site and got the new version of the same thing for 1/2 the price.
Did you get it repaired under warranty? If not, how much did it cost you to get it repair? My Nov'16 just hit this.Well, looks like I am another victim of this problem. MS 90D, Oct '16, 110,000 miles. I will be contacting service center tomorrow
Gtech
Active Member
Just had this same issue in my car, Nov 2019 build Raven with 17000 miles. Hope the mobile ranger can fix it as the nearest service center is 2 hours away. The manual release inside the trunk doesn’t work and I don’t fancy having to pull the car apart when it’s still under warranty.
Please keep me posted. This is def a safety issue that should be reported to NHTSA and covered under a recall (service bulletin or whatever we call it). Just happened to me and wth is that cable for if it doesn't even do anything?
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