08 ML350 Lift Gate Not Opening With Smart Key
- Lift gate does not open when using the Smart Key. It will make the unlocking noise, then lock closed after a few seconds. It also does not make the warning "beep" noise.
However....
- Will open with the rear handle, and close when the red button is pushed.
- Will open/close when using the driver door control
- Will CLOSE when using the key, if it is already open.
Do you have any cracks at the trunk button?
Does your LED light up when held more than 1 second?
Did you ever have any water entry in the spare tire area?
Please copy and paste the questions and answer along each.
- Do not have keylessgo
Do you have any cracks at the trunk button?
- I have 2 keys. 1 key does have cracking on each of the buttons. The other key has no cracks. (see picture below) Both keys exhibit the same behavior on the car.
Does your LED light up when held more than 1 second?
- Yes both keys LED will light up when each button is held. *EDIT* - Batteries in both keys were replaced when I purchased the car
Did you ever have any water entry in the spare tire area?
- I bought the car ~1 month ago. We did inspect the spare tire area, and saw no water. I just checked it again, and it is 100% dry.
Please copy and paste the questions and answer along each.
Last edited by Saeo; Jan 20, 2019 at 10:24 AM.
Where do you live? What's the weather there? Would you be able to remove a tail lamp?
Let me look into this and will get back to you within 2 hrs.
Last edited by Maj. Dundee; Jan 20, 2019 at 11:11 AM.
- Columbus, OH. Weather can be 65 one day, and 25 the next. However, the lift gate was doing this from the day I bought it, and the weather did not affect it.
- This (tail lamp removal) may be something I can try once we get rid of some of this ice. Would it be the right rear tail lamp?
When you use the key and it starts to open, are you able to manually lift the gate to assist full open?
- Yes, we did test this, and it will open fully.
Do you have a scanner?
- Do not have a scanner
Look at the all the codes for the Tailgate Module.
When the weather is on your side, remove the right rear tail lamp and see if the foam seal is attached to the tail lamp or attached to the body opening. In either case do not disturb the seal and reinstall the lamp. Let me know.
In the mean time I will research this problem, which is very puzzling.
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I had my local shop scan the car for any hidden or stored codes with a regular OBD scanner, as well as a Star scanner, and nothing was found. Since this time, I am plagued with more electrical gremlins, which I suspect is the reason why the rear hatch may not open with the key?
- Left rear reverse light malfunction
- Right rear fog/tail light malfunction
- Rear camera will not function when the left reverse bulb is installed. (I would imagine that the camera is tied in to this circuit)
I probed for ohms: bulb and bulb holders are good. I probed for voltage on the contact points of the tail light housings and I only get 6 volts to the terminals. With the bulbs installed voltage drops to zero.
Possible solutions:
- Fuse/relay issue?
- Grounding issue?
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First remove the right rear tail lamp and see if the foam rubber seal is attached to the lamp. If it is, do not touch anything and reinstall the lamp.
Post back with results.
I had my local shop scan the car for any hidden or stored codes with a regular OBD scanner, as well as a Star scanner, and nothing was found. Since this time, I am plagued with more electrical gremlins, which I suspect is the reason why the rear hatch may not open with the key?
- Left rear reverse light malfunction
- Right rear fog/tail light malfunction
- Rear camera will not function when the left reverse bulb is installed. (I would imagine that the camera is tied in to this circuit)
I probed for ohms: bulb and bulb holders are good. I probed for voltage on the contact points of the tail light housings and I only get 6 volts to the terminals. With the bulbs installed voltage drops to zero.
Possible solutions:
- Fuse/relay issue?
- Grounding issue?
I have to leave early and will address these problems when I return at 3PM.
All the lights and the camera are controlled by the rear SAM. Even though you said you checked the spare tire area for water, it could very well be that there was a previous water entry, it dried up and now you are having electrical problems.
The rear SAM sits on a ledge of the spare tire area directly below the right reart tail lamp. You should remove it and remove the black plastic covers and see if there is any corrosion. See videos.
I was hoping this would fix the rear hatch issue, but alas, it did not.
-The hatch will not open when using the key. Additionally, it will still not make the warning "beep beep beep" noise when the key is used.
- The hatch will close (if it is previously opened via another method) when using the key and will make the warning "beep beep beep" noise.
Did you remove the black towers and clean under them?
Also you should order two new tail lamp seals and install them on the body opening and not on the tail lamp.
Last edited by Maj. Dundee; Apr 23, 2019 at 01:11 AM.
- I did not. When I looked it the first time, I assumed they were soldered to the board. I looked at it again just now, trying to pop the towers off, but they will not budge. Are they soldered to the board, or do they pop off with the little black clips underneath?
Also you should order two new tail lamp seals and install them on the body opening and not on the tail lamp.
- Will do this
Follow up question. Should this empty post have a connection to it?
So my issue is, without the sam the car is not drivable, and the sams modules are not plug & play. They need to be programmed via Star? So at this point, do they even make the same for my vehicle anymore, because i couldnt find my part number: A 0164 540 17 01. Should i go to the dealer?
What is your full vin#?
Last edited by Maj. Dundee; Apr 25, 2019 at 04:37 AM.
You rear SAM number has been replaced by 164 540 22 01.
https://www.ebay.com/sch/i.html?_fro...02201&_sacat=0
I would buy the $299 one about 10 or so down the list. But whichever one you decide on, I would remove the covers and check the board.
A used SAM will start the vehicle with no problem the only thing that might be a problem is if you had a feature (e.g. auto tailgate opening) and the used one did not. Then those features will have to be coded into the SAM.
- Got the new SAM and had Mercedes program it. The hatch would still not open with the key.
- After re-diagnosis they found the latch needed replaced as it was not releasing properly. Additionally, once they tore the hatch apart, the found the backup camera control unit to be almost rusted completely out, so this was replaced also.
- I replaced the lamp seals also.
Do you want to remove the door liner to check the switch?


