1991 Mercedes Benz 560SEL wiper motor

[alabbasi]

All

I am only able to run my motor on high, I replaced the relay in the fuse box with a used on and it worked for a while and then did the same thing. I also replaced the combo switch with a new one and it did not help. I think I may be down to the motor, but it does not make any sense to me that a motor would work fine at high speed but not at low or intermittent.

Thoughts would be appreciated.