Mike... yes, tailgate open, accuator locked. I was able to get accuator in open position. However, I know if I close the gate I won't get it open. No activity at that lock when door locks open / closed. Think accuator took a dumb. Now I need to find one. Thanks,
Also replaced relay..no luck.
Thank you for response. You state vin# required for actuator to assure correct part. So, for example..... I go to Rock auto, enter search for tailgate actuator... '03 ML500... one part comes up for my make/model & states "alternate/OEM # 77114385. How do I know this is correct part, look for # on part removed? How many options are there for this part?
A few years ago I had the same problem. If I remember correctly I fixed it by pressing the buttons on the electronic key while holding the latch open and moving the door up and down. Eventually it will release.
Installed tailgate lock assembly and problem solved. A clue that it was a lock assembly issue all along.... the rear cargo lamp, set in the auto position, would not shut off when tailgate was closed. I shorted out the lock assembly and lamp went out.
Wish I had checked that from the get go.