1992 Mercury Sable bad windshield wiper governor

1992 Mercury Sable mileage: 114,500. I have a bad windshield wiper governor and I would like to know where it is located. I have looked at the switch, it is in perfect working order, and I can hear rapid clicking coming from behind the dash when the wipers are not working correctly. I have come to my conclusion based upon the following: 1. Wipers will not wash windshield when wipers are on (intermittent, slow, or fast) 2. When wipers are on intermittent, they will stop in various places on the windshield. 3. Wipers work fine in slow or fast mode. 4. Motor sounds like it should sound. Thank you for your help.