GL450 (2007) New Hatch Latch Actuator Unpowered
01-13-2019, 10:20 PM
#1
GL450 (2007) New Hatch Latch Actuator Unpowered
This post is in reference to a Mercedes-Benz GL450 (X164) 2007.
I just installed a brand new hatch latch actuator assembly and it does not function. That is, when the hatch closes (using the key fob or door switch) it will mechanically lock but not provide the final whirring and click to secure the door. Further, when the hatch is opened (using the key fob, handle, or door switch) it will fail to unlatch and the door motor will give up after a few seconds. I have to climb in the car and pull the manual release to get the hatch open. It is as if the actuator does not receive power to latch shut or latch open.
From videos on YouTube, there is a clear actuation noise on open and close that is simply not present with this new actuator. The defective unit I replaced would make this actuation noise as well, even though it failed to unlatch. This is a different failure mode. It’s as if the new actuator is not being driven at all.
I have verified that the connector is properly oriented and fully seated into the actuator assembly. I have also verified that the two hatch fuses (fuse 40 in back and fuse 105 in front) are not blown.
Does the GL450 have a hatch sensor that if it were malfunctioning it could lead to this issue? Does the car need to be taught or programmed in any way to accept new hardware? It seems unlikely but what are the odds that I was shipped a defective actuator?
In addition to this post, I have also sent an email to the vendor that I bought the assembly from on Amazon. I specificially chose Amazon despite being a bit more expensive, in the event I needed to return the part.
I just installed a brand new hatch latch actuator assembly and it does not function. That is, when the hatch closes (using the key fob or door switch) it will mechanically lock but not provide the final whirring and click to secure the door. Further, when the hatch is opened (using the key fob, handle, or door switch) it will fail to unlatch and the door motor will give up after a few seconds. I have to climb in the car and pull the manual release to get the hatch open. It is as if the actuator does not receive power to latch shut or latch open.
From videos on YouTube, there is a clear actuation noise on open and close that is simply not present with this new actuator. The defective unit I replaced would make this actuation noise as well, even though it failed to unlatch. This is a different failure mode. It’s as if the new actuator is not being driven at all.
I have verified that the connector is properly oriented and fully seated into the actuator assembly. I have also verified that the two hatch fuses (fuse 40 in back and fuse 105 in front) are not blown.
Does the GL450 have a hatch sensor that if it were malfunctioning it could lead to this issue? Does the car need to be taught or programmed in any way to accept new hardware? It seems unlikely but what are the odds that I was shipped a defective actuator?
In addition to this post, I have also sent an email to the vendor that I bought the assembly from on Amazon. I specificially chose Amazon despite being a bit more expensive, in the event I needed to return the part.
01-15-2019, 06:51 PM
#2
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This post is in reference to a Mercedes-Benz GL450 (X164) 2007.
I just installed a brand new hatch latch actuator assembly and it does not function. That is, when the hatch closes (using the key fob or door switch) it will mechanically lock but not provide the final whirring and click to secure the door. Further, when the hatch is opened (using the key fob, handle, or door switch) it will fail to unlatch and the door motor will give up after a few seconds. I have to climb in the car and pull the manual release to get the hatch open. It is as if the actuator does not receive power to latch shut or latch open.
From videos on YouTube, there is a clear actuation noise on open and close that is simply not present with this new actuator. The defective unit I replaced would make this actuation noise as well, even though it failed to unlatch. This is a different failure mode. It’s as if the new actuator is not being driven at all.
I have verified that the connector is properly oriented and fully seated into the actuator assembly. I have also verified that the two hatch fuses (fuse 40 in back and fuse 105 in front) are not blown.
Does the GL450 have a hatch sensor that if it were malfunctioning it could lead to this issue? Does the car need to be taught or programmed in any way to accept new hardware? It seems unlikely but what are the odds that I was shipped a defective actuator?
In addition to this post, I have also sent an email to the vendor that I bought the assembly from on Amazon. I specificially chose Amazon despite being a bit more expensive, in the event I needed to return the part.
I just installed a brand new hatch latch actuator assembly and it does not function. That is, when the hatch closes (using the key fob or door switch) it will mechanically lock but not provide the final whirring and click to secure the door. Further, when the hatch is opened (using the key fob, handle, or door switch) it will fail to unlatch and the door motor will give up after a few seconds. I have to climb in the car and pull the manual release to get the hatch open. It is as if the actuator does not receive power to latch shut or latch open.
From videos on YouTube, there is a clear actuation noise on open and close that is simply not present with this new actuator. The defective unit I replaced would make this actuation noise as well, even though it failed to unlatch. This is a different failure mode. It’s as if the new actuator is not being driven at all.
I have verified that the connector is properly oriented and fully seated into the actuator assembly. I have also verified that the two hatch fuses (fuse 40 in back and fuse 105 in front) are not blown.
Does the GL450 have a hatch sensor that if it were malfunctioning it could lead to this issue? Does the car need to be taught or programmed in any way to accept new hardware? It seems unlikely but what are the odds that I was shipped a defective actuator?
In addition to this post, I have also sent an email to the vendor that I bought the assembly from on Amazon. I specificially chose Amazon despite being a bit more expensive, in the event I needed to return the part.
01-20-2019, 07:24 PM
#3
I had the same issue when I replaced the trunk latch actuator. The replacement latch would sound like it is trying to pull the door in, but wouldn't. When opening with the key, it wouldn't release the door and I'd have to open it manually from inside. I ordered another replacement part, from a different vendor, and it worked perfectly.
I found a discussion online that recommended unplugging the rear SAM to reset it. After a bit of disassembly and wrangling I managed to do this, however it still did not fix the issue. Are there any ideas on next steps, for example diagnostic tools that can read SAM error codes.
02-17-2019, 07:49 PM
#4
I bought an iCarsoft MBII scanner to dig a bit deeper into the issue. After spending some time familiarising myself with the hardware and testing the hatch, I am fairly confident that the Rear SAM is functioning properly. I was able to see the Rear SAM sending signals to the Hatch Actuator Assembly (A72) coupling motor and drive motor. When closing, the coupler motor signal would move from OFF → BACKWARD → OFF and the drive motor from OFF → FORWARD → OFF. I am assume these are the signals the drive the rotary tumbler to the second detent (the final latch whirring that pulls in the hatch shut).
My thought now is that it could be the wiring assembly. I’m going to do continuity checking on the cable tomorrow. Possibly related is that the wing windows are showing an error that the obstruction sensors are not connected. I’ll follow up on those to see if they are part of the same wiring assembly (doubtful). If the wiring assembly is fine, then perhaps together this is evidence that the Rear SAM needs a closer look.
My thought now is that it could be the wiring assembly. I’m going to do continuity checking on the cable tomorrow. Possibly related is that the wing windows are showing an error that the obstruction sensors are not connected. I’ll follow up on those to see if they are part of the same wiring assembly (doubtful). If the wiring assembly is fine, then perhaps together this is evidence that the Rear SAM needs a closer look.
