Hello,

I've been googling and asking around and since no one that I talked to IRL had a reasonable answer to my problem, I want to try my chances here.

I have a 2017 CLA 45 AMG Shooting Brake that I've owned for around 7 months now.

A month ago, someone broke my rear windshield, and I had to go to a glass workshop and order up a new one. The new one came, and they fitted it onto the car. In the process of fitting the new windshield on the car, the employee managed to spill broken glass from the old glass, into the hydraulic pump/pole which raises the trunk up and down. So the trunk wouldnt work electronically. He ordered a new pump and replaced it , and the trunk worked normally with key fob, trunk button, and everything looked fine. After driving back home, 5 minutes into the drive, I got a "trunk open" warning on my dashboard, with an image of the car and the trunk part highlighted in red. Pulled over and went out to the back, and tried closing and opening the trunk a few times. I noticed that the two clicks you are supposed to hear when the lid latches on, were not there. I had to go to work so i didnt have time to go back to the workshop. While parking I also saw my rear camera wouldn't work because the car detected/thought that the trunk was open. The car also wouldnt blink 3 times when locking it, since it thought a door was open.

I called up the workshop and explained the problem, and they offered to come to my workplace and run diagnostics on the car to see if it needed some kind of calibrating or clearing fault codes. Before they were supposed to come, i went down on my own to the parking lot and tried fixing the issue myself - I tried closing and opening the trunk several times, and then tried doing the same with the button on the driver side door. I then put the car in reverse and the rear camera activated. I thought i had fixed the issue up until last week. The past week , when i open and close the trunk, 9/10 times it wont "detect" as closed, and i will still get the trunk warning light on my dash. 1/10 times it will actually close properly and the car will blink when locking, and no warning on dashboard. The problem here is, that after driving a while, i will suddenly get the trunk warning light. Once I also had to get up in the middle of the night because the alarm went off, and the car thought someone was breaking into it. But it was just the trunk going from locked to "not locked" according to the car status.

Sorry for a lengthy post, but this has been bothering me for quite a while. I have an appointment with the mercedes dealership on June 10th, but my fear is driving the car until then, that suddenly i'll look into the rear view mirror and see my trunk wide open.

Has anyone else had this problem? The weird thing is that 9 times the car wont detect the trunk as locked, but 1 time it will detect trunk locked, but it will still eventually detect the trunk as unlocked once im driving, or the car has been parked for a while.

I also notice that when the trunk is supposed to latch onto the post, it tries latching, then it seems like it failed latching, because the trunk will come back up around half an inch or so.

What i know in hindsight, is that the damn glass workshop didn't disconnect the car battery when disconnecting all wires/electronics in the back, to fit the new windshield, and when removing the plastic covers to vacuum up all the old broken glass.

Did they not vacuum all the glass, and some old glass is still in there ripping up wires?
Did they not connect everything properly?
Did they misalign latch to the steel post somehow?
Sensor problem?
Does the car need to be calibrated after changing rear windshield / hydraulic pump?

I appreciate any answers.