how to open mercedes hood when stuck and cable wont work

Giving you a thumbs-up for the idea of using an inflatable wedge. That exact method didn't work on this car I have, but I did use a wedge to put upward pressure in the middle while I pulled the release lever inside. This GLC300 had been in a prior collision and the body shop didn't get it aligned back totally straight. So opening the hood means you need someone to slightly pull up on the front edge while the other person pulls the release lever.

I have same issue on my 07 s550 was working on it and accidentally hit the latch and when I went to close it the passanger side locked but driver didn't.

yea, i dont have those instruments