1. Fuses and Relays:
* Locate the fuse box: Your owner's manual will show you the location(s) of the fuse box(es). Find the fuse(s) related to the wipers (often labeled "WIPER" or "WINDSHIELD WASHER"). Check them for continuity using a test light or multimeter. Replace any blown fuses.
* Locate the wiper relay: The relay is an electromechanical switch that controls the wiper motor. The location varies by vehicle; consult your owner's manual or a wiring diagram. You can visually inspect the relay for any signs of damage, and if possible, swap it with a known good relay of the same type (for testing purposes only). A clicking sound when you activate the wipers but no motor action suggests a possible relay issue.
2. Wiper Switch:
* Check the switch: The switch itself could be faulty. Try all the wiper settings (low, high, intermittent). If the switch is internally broken, the motor won't receive power regardless of fuses and relays. Testing this requires a multimeter and some knowledge of electrical circuits; a wiring diagram would be helpful. Replacing the switch is often the next step if other components check out.
3. Wiring and Connections:
* Inspect wiring: Check all wiring connections related to the wiper motor, switch, and relay for corrosion, loose connections, or broken wires. Pay close attention to the harness where it enters the firewall and near the wiper motor itself, as these locations are prone to wear and tear. Clean and tighten any loose connections.
* Continuity test: Use a multimeter to check for continuity in the wiring between the switch, relay, and motor. A wiring diagram is essential for this step.
4. Wiper Motor:
* Access the motor: The wiper motor is typically located under the hood, usually near the base of the windshield. Accessing it may require removing some plastic trim pieces.
* Visual inspection: Look for any obvious signs of damage to the motor itself, such as corrosion or burnt components.
* Direct power test (Caution!): This is the most involved step and should only be done if you're comfortable with automotive electrical systems. With the motor disconnected from the wiring harness, carefully apply power directly to the motor using a battery and jumper cables. Be very cautious to avoid shorts. If the motor runs, the problem lies elsewhere in the circuit. If it doesn't, the motor is likely faulty and needs replacement.
5. Ground Connection:
* Check the ground: A poor ground connection can prevent the motor from operating. Trace the ground wire from the motor to its connection point; clean and tighten it.
Important Notes:
* Consult a Repair Manual: A repair manual specific to your 1993 Pontiac Transport is invaluable for detailed wiring diagrams, component locations, and troubleshooting procedures.
* Safety First: Disconnect the battery's negative terminal before working with any automotive electrical components.
* Professional Help: If you are not comfortable working with automotive electrical systems, take your vehicle to a qualified mechanic for diagnosis and repair.
By systematically checking these items, you should be able to pinpoint the cause of your non-functioning wiper motor. Remember safety first, and if you're unsure about any step, seek professional assistance.
