where is the windshield wiper circuit board located on my truck? on 1990 Chevrolet 1500 Pickup

the windshield wipers and washers are not working properly on my 1990 chevy k1500. the washer will not work at all and the wipers will work but not all the time. I've read that the problem is a circuit board that controls the wipers but where is it located?

I believe that the circuit board's part of the motor assembly. I don't have good info on that system anymore so I have to rely on my memory. I'd check the connections at the motor, for looseness or corrosion, that's a likely problem.
An auto electric shop or a GM specialist would be good resources.
Here are two online sources for you for more information:
For AllData:
Here's the one for Mitchell as well:
If you want to find a GM specialist, here's our directory link for you: