Our 1996 Mercedes C 250 single arm wiper has intermittently over 4 years
operated with difficulty. It struggles, almost stalls at two points across
the windscreen - appear to coincide when the blade arm performs its cunning
extention and withtraction trick.

If it were possible to dismantle to give something a drop of oil or smear
of grease I imagine it would greatly relieve the problem. This problem is
causing electrical load problems as I noted the steering wheel control
stick was getting hot as well. Could it be a loose electrical connection
causing the problem with nothing mechanically wrong with the wiper arm
system? I understand the latter rarely give problems.

Any experience with this one greatly appreciated - thanks.