Georgetech

Hi, everyone
I installed the OEM hitch in my 2004 ML350 six month ago whithout any problems smooth installation. In my opinion I was ready to go just waiting for this time of the year to take my boat out of the water, well guess what yesterday I hook-up my trailer and only the running lights work,no brake or signal works. I checked the bulbs and they are OK! I hooked my old Ford Explorer to the trailer and everything works. have anybody else encounter this problem? Do you think is a defective module box or the wiring harness was assembled wrong from factory. I called my dealer where I bought the OEM hitch and the say there is no warranty because I did the installation. Any advise? should I go and buy the module box by itself or should I buy the wiring harness again?

ChampML

I had the same problem couple of months back.. Until I remembered a posting here about checking for the fuse. The fuse (I forget the fuse number) is not installed at the facory. I believe it is a 20 A. Good luck

KyVan

I had the same problem. Your converter may need to be replaced.
Check this out.

http://en.wikipedia.org/wiki/Trailer_light_converter

Good luck.
Kyvan