Okay boys and girls here we go:

I get in my 05 SUT last week. It's raining out and I have the wipers on intermittnet. Out of nowhere, the washer pump starts pumping washer fluid. I have to turn the wipers up to keep everything clear from the pump and the rain. The pump keeps going and the wipers quit working on anything but high. When I turn them off or even down, they stop where they are without resetting to the bottom and the pump continues. Eventually I run out of washer fluid but the pump keeps going.

When I get where I'm going and shut the rig off and restart, the wipers are operating normally but the pump is still going. I removed the relay from under the hood to get the pump to quit.

Any ideas as to what may be the culprit?

 

some guesses , its a messy circuit with a lot going on. wiggle the turn sw,see if any intermittents. swap similar relays,see if problem moves with a relay.
obvious, double chk fuses.
the motor has nothing,no electronics like i had in a similar prob/pontiac, thats good. the bcm seems to do a lot, that could be bad, but its probably a signal,sensor,switch feeding it.
back to the turn sw that does everything but shift gears. thats my suspect.

many yrs ago i had a pinto wiper reoccuring prob.
i rigged a screendoor spring on one side and a pull cord on the left.
never had a failure!!

 

I was thinking the same thing and hoping that it's located in the turn switch handle itself and not the wiring harness or steering column. Going to give it a look tomorrow and see what I can find out.

Thanks for the tips.

 

Same problem.
The washer keeps running. I tried swiching the relay, didnt work. I tried a new turn switch handle didnt work. I tried cleaning and using non elec grease on the cicuit board that on top of the wiper motor didnt work, I read that some were. I have power running to the plug going to the washer motor when you turn the key on. I have try talking to some GM mech, but they said just bring it in or call back later. Lost at as to what to try next. Maybe a rain dance?