On the drivers side engine firewall.
Check to see if it a factory recall first. I have a '95 Astro 4.3L V6 and it had a recall for the wiper motor because they would do some crazy things on their own. The dealership replaced it free of charge.
The wiper motor doesn't turn off until the wiper arm gets to the "park" location. If the wiper motor never detects park, the wipers will stay running.
The metal panel between the hood and windshield is removed to service the wiper motor.
try checking the fuse. check the plug that goes into the wiper motor.
There is a switch inside the wiper motor that identifies the home spot for the wipers. If you have intermittent wipers there is also a controller for that. Either can give you problems but more likely the wiper motor switch. The wiper motor switch usually is not a separate part (comes with wiper motor assy.) Oh yeah, 1 other thing, be sure the wiper arms are installed correctly on wiper motor.
IT Has 1 you can disassemble the cowl lever & wiper motor to get to it.
Remove the wiper arm from the wiper motor. Remove the wiring harness from the wiper motor. Remove the wiper motor retaining bolts. Reverse the process to install the new wiper motor.
If its like a 96 you remove the windshield wiper motor and assembly
Remove the wiring harness from the wiper motor. Remove the windshield wiper arm from the wiper motor. Remove the wiper motor retaining screws. Reverse the process to install the new wiper motor.
The shaft from the motor to the wiper actuating arms is possibly stripped or disconnected. You will need to trace the wipers back to the wiper motor to find the problem. As mentioned follow the linkages back to the motor as they sometimes pop out of their cups.
Wiper arm travel rod from the wiper motor. Remove the wiper motor wiring harness. Remove the wiper motor retaining bolts. Reverse the process to install the new wiper motor.