Jim Dilks

I seem to have a wiring problem on the control unit. can I fix it?

MRPerformance

Not uncommon for those units to fail as a result of clogged drains and water getting into the trunk. Lots of people have successfully repaired them but there's no way to tell until you get into it. Plenty of info on this problem on the SLK specific forum.

Jaron

The controller sits in a foam box made of a material similar to carpet padding. Water leaks down into it, but does not have a way back out. Mine stopped working after I left the trunk open during a rain storm. I pulled the battery terminals to halt any corrosion (you'll need your radio codes if you do this. Mercedes tech support can give them to you), then located the controller (passenger side, forward from the roof pump), drained the water out and let it sit until it was dry, then when I put it back in I threw away the bottom half of the foam box that had been allowing water to accumulate.