If the picture posted above in message #24 is not good enough for your mechanic to locate this part, then you definitely need another mechanic.

The pictures you posted do not look accurate to me (at least they are not representative of an ML430) but could be a view convenient for a camera but not a person.

Candidly, at first this is a difficult part to locate. You'll see it before you can actually touch it.

Lay on top of the engine, get your head as close to the firewall as you can and look at the most rear section of the engine that you can....near where you would expect it to meet up with the torque converter. You will see a single wire. It is NOT with a bunch of other "stuff" or other wires.

Good luck.

__________________
Jim