[ab72756]

The wipers won't always start when turned on or stop when turned off. Sometimes run in a non selected speed or just stop in mid stroke. This is obviously a problem in the control circuitry.
My question is where is this circuitry located?

 

[McLaren]

It's the wiper control module. It's attached to the wiper motor on the firewall with three torx screws. GM issued a recall on these wiper modules involving almost 2 million vehicles, so you may want to check to see if yours was involved in the recall.