Andres Morejon

Hello, my dads 2008 GL550 did not have any form of hitch on it. I installed an OEM hitch into the frame rails and it replaced the crash bar and all of that. Connected the black connector to the rear SAM, the brown cable to ground and the red cable with the fuse to the brown slot in the fuse panel. When connecting to a trailer there is no acknowledgment in the car of a trailer and NO lights work. No power or anything. What is a sure way to know I did not mess anything up and the SAM just needs to be reprogrammed? He was quoted nearly $350 to just reprogram and want to make sure its necessary. The hitch harness still has a green connector (brake controller) not connected to anything as there is no recieving plug there. Any guidance would be amazing. I have looked through forums and I have heard the suspension won't raise but is this true? Also, dealer seemed unsure if it actually needed to be programmed when called. Any ideas? Thanks

Max Blast

Short answer is to plug a trailer in and see if it works.

And no, it won’t raise the car if you have a trailer plugged in that will overtax the system.

If it is necessary to program a hitch, and it probably would be in the developer submenu under ziehenlenkung eingebaut from no to yes.