Tailgate does not latch by tailgate button

Tiny
DPTRAN
  • MEMBER
My ML500 2006 having liftgate issue. At first when we close the trunk, it won't close perfectly, then, when we use hand to touch the latch (to open the trunk) then we hear the sound noise and the gate closed, Or if we leave the trunk as is then when we started the engine and drive it display the message "gate open" (or something like this) then about few minutes, you would hear the sound/noise from the trunk and it is closed.
Then just last week, when open and close the trunk we heard the noise from the motor keep running non-stop! I drove the car to the auto repair shop and the technician helped to open the panel and remove the wire so it stops making noise.
I ordered a new liftgate actuator from Amazon and the technician helped to replace the all one. Then I could close the trunk perfectly for the first time, then when I open and close the trunk the 2nd time, I do not hear the sound of trunk closing. At this time, I could not open the trunk any more. However, when I was driving the message displays "tailgate open" and within a minute I heard the trunk closing (okay). Then when I park the car, I could open the trunk, close it the first time perfectly, but when I open and close the trunk the 2nd time, it will repeat the same issue as described above.
The auto repair shop technician suggested me to buy the "Rear SAM module" because he suspect it is bad. This rear SAM module cost $300 used one.
I really want to ask is the SAM the culprit? What went wrong with the SAM, can we clean it (how?) To make it good contact?
I really appreciate for your help, support
Best regards,
Tony
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
KASEKENNY
  • EXPERT
Can you get a video of this operating properly and then how it does not operate properly the second time? I am pretty sure I understand what it is doing but seeing it would really help.

As for if the SAM is the correct issue, just on the surface I would not agree.

This sounds like a control issue because clearly the latch and motor operate properly as they work the first time. So if they can do it once, they should be able to do it all the time. The fact that they are not and then as you are driving it then closes, again shows the components can do it, they are just not doing it when they are supposed to. That is a control issue.

However, the SAM module just gets the signal from the key and other inputs and tells the Rear end door closing module what to do. This module is what actually performs these functions.

I attached some info on this. Do you have a scan tool that can monitor the components to watch the request states? Meaning when you press a button the rear end module should see that and then command the latch to release and the motor to open/close the door. If it is doing this then we may have a motor issue. However, I suspect we will find it is not which is the proof we need.

Take a look at this attachment below that illustrates this pretty well.
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
DPTRAN
  • MEMBER
Hello KaseKenny1,

Thanks so much for your time looking into the issue in details.
Attached please see the clip video of how it has been happening. It happened exactly that I did explain, first time open the trunk no issue, close it no issue hearing the closing sound uh uh uh. Then open it second time ok, however, closing it hearing no sound, then could not open the trunk.
Then driving, see the message "tailgate open", keep driving few miles some time 5 min, some time, 8min randomly, then hearing the closing sound uh uh uh. Then when we stop, we could open the trunk the first time, then close, then open 2nd time no issue, but closing the second time having hearing no sound and can't open it. The issue repeatable like this.
I don't know how to fix it, I did using dirt cleaning, wd40 to clean a bit but no help.
I might have to end up buying the rear SAM Module and try it. Thanks so much for your advice.
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
DPTRAN
  • MEMBER
I don't have a scan tool.
Tony
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
KASEKENNY
  • EXPERT
Okay. I would not do the SAM yet. After seeing that, I think the issue is the latch itself. The reason is, I think when you close it, it is getting slammed too hard and that damages those latches. I have not seen this in a Mercedes but have in a bunch of Fords and the latch basically operates the same.

The way they work is when the latch senses the striker, it actually pulls the door shut which is the noise that you are hearing. The noise is the motor in the latch that is pulling it shut. When they get closed too hard it damages the sensor in the latch and will not operate properly.

This doesn't explain why it works the first time but will you try something for me? When you close the door, close it very softly almost to the point where the door will rest on the latch and then you have to push it softly until it trips the latch and the motor pulls it in. Then operate it again the same way and see if it continues to work.

Since you don't have a scan tool, I would still replace the latch before the module, even if that doesn't work.
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
DPTRAN
  • MEMBER
Hello KASEKENNY1,

Thanks a lot for your comments.
I will try to follow your instruction to close the trunk softly tomorrow and let you know the result.
In my earlier email, I have mentioned that I have seen this issue, phenomenon few months back until 2 weeks ago, when I opened the trunk and closed it, I heard the motor keep making noise uh. Uh. Uh. Then stop then uh. Uh. Uh then stop and continue doing that so I have to drive to the auto repair shop for technician to remove the panel and unplug the wiring.
Then I bought the new Tailgate Trunk Lift Door Hatch as shown in image attached and replaced it.
Therefore I'm not sure "the latch" that you mentioned is the Tailgate Trunk Lift Door Hatch that I bought or something else?
Appreciate that you could give me the part # or the image so I could buy to replace it
Thanks a lot for your advice.
Tony
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
DPTRAN
  • MEMBER
Hi,

I have tried to close the trunk gently/softly but it did not help.
Thanks,
Tony
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
KASEKENNY
  • EXPERT
Okay. That answers that. Then I am back with you on the control module. If it were me, that is what I would do next.

Let me know what happens with this one. Thanks
Was this
answer
helpful?
Yes
No
Thursday, February 18th, 2021 AT 1:34 PM (Merged)
Tiny
DPTRAN
  • MEMBER
Replaced Rear SAM Module bought it on eBay for $299.00, it works perfectly. Could not believe that how the defect rear SAM module behaving like explained earlier.
Thanks so much Kasekenny1 you are awesome. This should be a good case study to share to everyone.
Tony
Was this
answer
helpful?
Yes
No
Saturday, February 20th, 2021 AT 8:34 AM
Tiny
KEN L
  • ADMIN
KASEKENNY1 is one of our best! Use 2CarPros anytime, we are here to help. Please tell a friend.
Was this
answer
helpful?
Yes
No
+1
Tuesday, February 23rd, 2021 AT 5:22 PM

Please login or register to post a reply.

Sponsored links