I have been lurking on here for a while, and until now most of my problems were fixed just by reading the forums.

I had a trunk issue 09 ML350 4Matic (W164). Originally, the trunk would go up and down, but would not close all the way, and even though it was not closed all the way, it would still lock and I could only open the trunk using the emergency release on the inside.

I figured it must be a malfunction with the trunk locking mechanism/actuator, and I ordered a new one on eBay and replaced it. However, when I put the new one in, I have more problems than before. Now, the trunk won't close or lock at all, and the lifgate only goes up and won't go down. When it goes up, it makes a grinding (grr) noise, and when I press the button on the trunk to go down nothing happens, when I press the button on driver's side door to go down, nothing happens, when I try closing it with a key fab, it does not go down but unlike the trunk and door buttons trying to close it with the key fab makes the grinding grr noise but the liftgate does not move.

I removed the spare tire, and got to the trunk hydraulic motor. The motor seems to work fine when the trunk goes up, but does not do anything for it to go down. I also topped off the hydraulic fluid in the white tank that sits on top of the motor. Still nothing.

I'm wondering if I broke the trunk hydraulic system motor when I tried to manually close the trunk or if I did something else. I ordered another trunk locking actuator which I will replace just to make sure the one from eBay is also not faulty, but that probably won't fix my trunk not going down. Anyone know what the issue here could be and if there is a fix without taking it