How do I test a windshield wiper motor to see if it needs replaced?

There is an active recall for that issue with your vehicle. Might want to check with a dealer near you about possibly getting yours fixed

Recall id# 11210 Recall Date: JUL 01, 1998 Model Affected: 1995 GMC Sonoma Summary: VEHICLE DESCRIPTION: LIGHT DUTY PICKUP TRUCKS AND SPORT UTILITY VEHICLES, 2 AND 4-WHEEL DRIVE. SOLDER JOINTS NEAR THE WIRING HARNESS CONNECTOR CAN CRACK CAUSING THE WINDSHIELD WIPERS TO WORK INTERMITTENTLY. Consequences: THIS CONDITION CAN RESULT IN INOPERATIVE WIPERS, REDUCING A DRIVER'S VISIBILITY, AND INCREASING THE RISK OF A VEHICLE CRASH. Remedy: DEALERS WILL REPLACE THE WIPER MOTOR CIRCUIT BOARD AND COVER. Potential Units Affected: 1557585 Notes: GENERAL MOTORS CORP. Read more: http://www.motortrend.com/cars/1995/gmc/sonoma/recalls/#ixzz2TgenrZ L1