shawninvancouver

i have tried three new power close motors and it wont pull the trunk latch closed.. i have to slam it to close.. there is power as it will open.. any ideas??
this is not the full lift gate open and close... just the latch close motor.. its not puling it to shut closed.... help!!

CaliBenzDriver

Please provide pictures of this issue, I will try to help you with that.

Would you say:
"It has power but is not latching" describes your situation?

shawninvancouver

yes,.i it has power but the latch wont pull the trunk closed.. get error message on dash - trunk lid not closes. dome light wont go off.. even if i slam it closed dome light wont go off and still error message.. i am not going to have the rear same module replaced as that may be the cause... whats your guess??

CaliBenzDriver

Let's not guess... TEST!

"Latch has power but is not doing anything to shut tightly", correct?

I think there is a sensor on the opposite side (moving hatch) and cable gets chopped after 5000 open/close cycles.

Test the GND to chassis is proper.

efzauner

You replaced the rear latch. Is that what you are saying? I have replaced it once with an inexpensive aftermarket and it worked well.
There is also the emergency open cable. Perhaps something jambed there.
You realize there is also a latch adjustment? you can loosen the screws on the chassis to reposition the closing loop.

shawninvancouver

where is the latch adjustement? the loop part is firm on the trunk area... i dont see any screws on it? yes.. i bought a cheap aftermarket latch motor before and it worked fine.. now a new motor will not solve the problem.. please tell me more...
oohhhh motor wont even close with a screw driver in the motor... that should work.. so i am not sure if moving the loop will help..

efzauner

hope you have not had back luck with bad parts.
Can you describe more symptoms? What is actually happening? No latching motion at all from the lock?

As for the latch adjustment: if it is too tight closing then the door may hit the protection strip and re-open. But seems this is not your problem
from service bulletingLiftgate reverses direction at the bottom when closing
Topic number LI72.20-P-053761

Version 1

Design group 72.20 Rear door, tailgate

Date 06-07-2012

Validity MODEL 251 from VIN end number A123392 to A145873

Reason for change Validity adapted
Complaint:
The automatic liftgate reverses direction at the lower end position when being closed.
Cause:
During the closing sequence the liftgate collides with the obstruction sensor strip, which triggers the anti-pinch protection function.
Remedy:
Adjust the liftgate by adjusting the striker.

The gap between the liftgate and the side wall should measure approx. 6.5 mm (see Figure 1).
Note:
It must be ensured that when the liftgate is closed there is a gap between the liftgate and the obstruction sensor strip along its entire length. This can be verified if it is possible to slide a piece of paper along the gap with no resistance

As for the latch adjustment, loosen the screws abit and move the latch around

shawninvancouver

thanks for some info.. be aware this is NOT a full closing liftgate, just a normal hand close hatch on the r350. my problem is the soft latch motor power close that just does the final close of the latch and pulls the trunk closed. i have used after market latch motor in the past and it worked fine.. now i have tried 2 other new amazon latch motors and both did the same thing as the one in the car now.. it wont pull latch closed. it has power and does the power open/ unlatch ( not a power liftgate). when this all started i had a message on dash - says liftgate not closed. then another message - liftgate malfuntion go to workshop. i can slam the trunk closed but still get all error messages. several shops think this is due to a bad rear SAM that controls rear locking system,, there is no water damage to that unit..

what else can i try????

Tsumi

You should bring the car to a mechanic that has Xentry that can actually diagnose the system. They can watch the sensors in Xentry and see if they're triggering or not. They can also probably manually trigger the motor in Xentry to check functionality. At this point throwing parts at the problem is not going to help you.

You can try searching the W164 and X164 forums for clues. They're essentially electrically identical to W251.

Minibenz

My rear latch does not always latch and I get a message advising it is unlocked. I have the driver door release for the liftgate and the red light remains lit when this happens regardless how it was opened or closed. Pressing the driver door release will sometimes complete the latch and the light goes out. Sometimes I partially raise the liftgate with this release and then quickly close it.....kind of like a little slam from inside the car. If I close the lift gate at the rear I will now usually give it a little assist just before it completely closes. Always works and keeps the aggravation level very low.

Minibenz

I did the adjusting this morning. Really easy enough to do. I simply loosened the screws, and visually center it up and it works perfectly now. Actually it was the first time I have ever heard the latch engage.

shawninvancouver

yeah.. but the latch does not even worth with a screwdriver in it.. i should be able to click it and hear the power close work.. i cant get it to do that.. the shop says its the rear sam.. could it be that???

shawninvancouver

it has power as its clicking away.. just wont pull the hatch closed... which it should do.. i tried 3 new latch motors... could it be the rear sam???

Minibenz

Have you tried to make the adjustments at the loop part? If you have not done this it would have to be the next for me. There is trim covering the screws but pretty easy to get to by removing two screws securing the trim and popping it out.

shawninvancouver

I have not tried the loop adjustment yet... but before i do that can anyone answer these questions??
1. should i not be able to flip the latch with a screwdriver and hear it do the final soft close on the screwdriver?? when i flip it all it does is click closed - no soft close.. the only power is when i pull the handle to open it... so a loop adjustment may not do anything....
2. Also... would a broken emergency release handle on inside of hatch effect this to stop working????? i have tried 3 motors and all same problem.. no soft close.. all have power when i pull the open handle.. but NONE will do the SOFT FINAL close....

the shop is saying its the REAR SAM module.. but all other lights and everything works fine.. its NOT a power liftgate... this is just the part to pull tailgate close..
its driving me nuts.. help!!!!