Thanks for the great thread. I just completed changing the rear hatch lock.

I have a 99 ML 320 with 40,000 miles and had the same symptoms as described above. I removed the rear panel and sure enough, the plastic piece that connects the actuator to the lock was broken. Got the part from the dealer ($97) and just installed it. Works great.

However, after I was done reassembling everything the liscense plate lights don't work. I checked the bulbs, they are o.k. I tried switching the hot and ground wires, but it still doesn't work. I checked the fuse (F9), looked good, but I changed it anyway, and still nothing.

Anyone have any thoughts about what may have happened and how I can correct it??????