Why don't my wipers work when I turn them on?
Check for 12 volts at the wiper motor (with switch ON) connection use a multimeter or find someone who can check for you.. I'm sure you have checked all fuses and or relays before even touching the motor.
Search Pontiac Grand Prix Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Pontiac Grand Prix Experts