Originally Posted by MB190D

Your car has one relay for each side, located underneath the floormats (and plastic grid). I had similar problems with my passengerside relay last winter; It would go on at will, and was almost impossible to control via switch. Sometimes it would just click like mad before settling to high or low after a few seconds. Considering the placement of these, they often rust, which will call for a resoldering (if lucky, replacement is next). I planned to do this, but before I got around to it the problem disappeared by itself. The seat is (or was, installed new seats which haven't been modified for it yet) fully functional still.


Edit; Just noticed that you had the same problem regardless of which relay you used; In that case the switches are probably defect - try swapping those around.