2001 gmc wiper problem, one speed.

I just recently purchased this truck. 2001 GMC k2500 with the 6.0l engine, with over 300 thousand kms. A few minor things but all in all, seems ok. The thing that's really bugging me is the wipers only work on the highest speed, they actually go how fast they are supposed to, but they don't work on any other setting, in addition when the sprayer switch is turned they spray, but the wipers don't cycle. Does this sound like it may be the switch.

I have done the circuit boards and motors on the older trucks but have never ran into a wiper problem on the 99-07 trucks like this. Any help on this would be great, thanks.

Something else I noticed that I thought I would mention, when the switch is to high they go at that speed, but when its turned down a few notches they stop dead on the windshield where ever they are at. I compared this to my '03 Silverado, and when its on high when you turn it down a few notches they just cycle down to the bottom then slow down to whatever setting they are at.

3 things to test. Wiper motor, pulse board or switch. Wish I could point you closer.

now that is a lot warmer out and I'm on vacation, I've been digging into this. I tried the motor from my '03 just to see if it changed, no luck, so I figured it wasn't the motor. I found the connectors at the bottom of the steering column for the multifunction switch melted, only the connector on the switch side, nothing visually where they plug in, so I thought I would try a used another switch, one that didn't have any melted connectors.

I purchased a used one, wanted to try the one from my '03 but the connections where different. but to no avail, still same problem. of course now, my left signal won't cancel and the hazard switch is messed up, so I figure the used one I bought was worn out aswell, but you would think the wipers would still work.

so now I'm wondering if maybe there is something with the module it plugs into at the bottom of the steering column. the ignition and airbag plug into it as well. I don't even know what it is. going to try to find a wring diagram to see what is all between the switch and the motor, hopefully I can find something.