Hello. I replaced the battery in my '07 ML350 the other day and now my liftgate will not close.
History:
The lift gate has never given me a problem. It would open on command and I've always closed it manually. I never tried to close it with the button because the girl I bought it from said it didn't work. But it latched every time.
Then I replaced the battery...
Dang. El no bueno.
The gate wouldn't latch anymore. I went on line and tried all these different solutions, but nothing worked. It wouldn't latch. Then I watched this video where this dude talked about doing a reset. He said to lift the gate half-way and then all the way while pushing buttons and all that to get it to "Learn". That was when my liftgate decided that it wasn't interested in learning anything. While it was wide open it said, "That's all I wanna know". And that was it. I couldn't even close it manually. Id slowly try to close it and it wouldn't let me get past the halfway point. It wouldn't just "Stop" half way, it was more like a spongy feel. Like I was closing against a pocket of air.
I went through all kinds of different procedures with the door switch and key fob and although the chimes were chiming ant the motors were running, nothing happened. So it spent the night outside with the hatch open.
I was somehow able to manually close it the following day. It didn't just close, I was pushing the door button, the hatch button, the button of the key fob, inventing new cusswords (all at random and in no particular order) and miraculously, the pocket of resistance dissipated and and I was able to lower it. It didn't latch, but it lowered.
Yesterday I disconnected the battery to do a hard reset thing. Instead of leaving it disconnected for 15 minutes, I ended up going 15 hours. Which brings to now.
And it's acting exactly as it was, and it's stuck once again, in the up position. And with these new burn laws in place, I can't set it on fire. So I don't know what to do.
Any suggestions?

Thanks.

 

Could it be an issue with the strut rather than the electrics? I had a similar issue on a prior vehicle where replacing the strut was the solution

 

Hey Stripey. Thanks for the quick reply.
Yeah, I've read all about those motor driven struts. They're a cool idea. One strut drives the lift gate up and down, and the other helps take the load off. Unfortunately, that wasn't complicated enough for Mercedes.
So they combined systems and added more moving parts.
The ML350 (well, mine anyway) is driven hydraulically. And I guess when there's a loss of power, the systems lose communication and stop talking to each other. So I'm guessing the hydraulic system doesn't know if the gate is opened or closed. It has to "Learn". But in order to get it to learn, I have to be able to close the gate. Which is why I'm here. I can't close it.
Thanks again for the reply.

 

You might need to clear all the low voltage codes from the battery replacement. You might find that it then works correctly.

 

Hi AL5641.
How would I go about clearing the low voltage codes? Is that something I can do myself, or is that a task for the seasoned mechanic? If it takes a computer, is the computer something inexpensive that I could buy on line? Or would that be impractical?
I'm one who would rather do it myself if I can.
Thanks for the advice.

 

ICarsoft do an MB specific tablet for about $200 this is all you need for code reading and clearing. It will read every module on the car, something that some cheaper OBD style readers struggle with.

https://www.icarsoft-us.com/products/mb-v3-0

The latest version:

https://www.icarsoft-us.com/products/icarsoft-mb-v4-0

Clearing low voltage codes with Xentry takes a while and the cheapest clones are around $1,000. This ICarsoft is much quicker for silly stuff like this but obviously doesn't have the full programming ability that the factory software has.