Joseph Sager

I replaced my ESL motor this weekend and had to disconnect the battery for about a day since it involved removing the airbag.

After reconnecting the battery, I noticed the power tailgate no longer opens or closes by motor. Pressing the trunk button on the keyfob, driver's side door, or button on the trunk latch all successfully unlatch the trunk but the power tailgate motor doesn't seem to be doing anything.

I checked the fuse 61 and it appears good.

Is there any chance the tailgate isn't working because the battery was disconnected and it needs to be reset or something? It seems like odd timing that the motor would just suddenly die without having any problems beforehand.

And are there any guides for replacing the motor? I wasn't able to find any online which makes me suspicious that the motor isn't a common point of failure. Most of the posts I could find about the gate failing talked about the car being new or the gate only working intermittently before failing.

calder-cay

Any progress on the tailgate problem? Seems like a one-off issue as a side-effect of the disconnect.

Joseph Sager

Unfortunately not, no.

I was hoping someone here would have an idea because the next obvious step is to take it to a shop that can hook up a Xentry or Star - whatever the Mercedes diagnostic computer is called - and see if the module has an error that they can read.

I pulled some more fuses the other day to check them but they all seem fine.

I have one of those iCarsoft i980 readers but I don't think it sees the module that controls the lift motor because I wasn't able to find anything that seemed relevant.

Mmr1

Just guessing , replace the relay and try a different fuse

calder-cay

Wild guess from me ... why would the relay fail, because the battery was disconnected (to replace ESL) ... a coincidence (?)

Joseph Sager

To replace the ESL you need to disconnect the battery while the steering column is unlocked so it's possible the relay or fuse popped when I reconnected power if the circuit was energized when I disconnected power.

Unfortunately, I don't see anything in the literature to indicate a different fuse for the liftgate or a relay labeled "liftgate."

If I find a different fuse popped, I'll update the thread for posterity.

Mmr1

I’m just guessing but I think a relay is needed for the power required to lift the tailgate . Is power measured on both sides of the fuse?

Odd Piggy

Does your reader/scanner read “B” codes? Those are for the body components like door locks, etc, and if there is a code for the lift gate it would probably be there. Less likely would be CANBUS communication codes “U” or chassis codes “C.”

More than likely there is a relay because it’s running a motor. But it may be a solid state relay (SSR) and not a mechanical one that’s plugged into one of the fuse or relay boxes.

Bamapartsman

Did you ever figure out tha issue? My GLK has the same issue!

Joseph Sager

Yes I did!
The tailgate needed to be "relearned" with Xentry.
I paid my local indy shop $127.75 (including tax) to do it.
It is appearantly a known issue.

Silver Shadow

Good to know.

Bamapartsman

Thanks! I have downloaded the xentry program and trying to load it...Now I know Im on the right road...
Gene