I can turn my windshield wipers on high and they work and so does my wash function but every other function fails even if I turn the wipers on high and try to turn them off they keep moving and I have to turn the truck off to get them to stop. I replaced the GEM Module and Multifunction Switch. I jumpered the wiper motor relays for both low and high and the the motor works at both speeds. I took all the resistance readings on the new multifunction switch to make sure they are within spec and they are. I have 12V on pins 13 and 15 and ground on pin 14 of the wiper control socket. I even went as far as making resistors to insert into the socket to mimic the multifunction switch settings and nothing except for the 2 funtions that work with the switch installed. I am at roads end ready to push this damn truck down a cliff unless someone can bring me to my senses!

 

Have your alternator checked. My MFS acted weird before due to popped diodes in the alt. Weird yes, but my 2000 might act the same as yours. Another idea is a thing called the clock spring. Never replaced one but I hear it is somehing to look into especially if the wiper functions are fine. Now thinking of it, the clock spring is what I'd put money on.

 

From what I have been reading the Wiper functions do not go thru the clock spring only the air bag, horn and cruise control switches. I have had this problem with this truck since the day I bought it used a few years ago. I also went thru about 8 batteries due to them completely loosing there charge overnight and one day I decided to get a used GEM module from a salvage company thinking maybe thats why my battery is dieing and my wipers don't work properly. When I replaced the module I noticed the one in my truck was made in Mexico and the one I was putting in was OEM made in Canada and now I haven't had a battery die yet in 4 months but my wipers still don't work! I also replaced my alternator thinking thats why my batteries were dieing.