New to BenzWorld/Please Help

I have owned a 1992 Merc 300SL for 2 years now which I absolutely love but there's a few problems I'm hoping someone may be able to help me trouble shoot....all of a sudden when the wipers are on pulse they stop on the windshield whenever and wherever they want... they are OK if they're on full but when you turn them off or on pulse that is what happens!? Also, around the same time....not too sure if it was exactly the same time....but the door locks and trunk no longer work with the fob or in conjunction with each other....you have to physically lock and unlock each door with the key....batteries and fuses are all good!? Any suggestions? I would GREATLY appreciate them!

K Mc