1. The Fuses: Check the fuse box (location varies slightly by model, consult your owner's manual) for any blown fuses related to the wipers. Look for fuses labeled "wipers," "windshield wipers," or a similar designation. Replace any blown fuses with the correct amperage.
2. The Wiper Switch: The switch itself could be faulty. Try wiggling the switch while someone operates it – a scratchy sound or inconsistent operation suggests a problem with the switch. Replacement is usually the solution.
3. The Wiper Motor: The motor might be seized, burned out, or have internal problems. You'll likely need to access the motor (usually under the hood, beneath the cowl) to check for power reaching it (using a multimeter) and to test its operation. If it's not getting power, the problem is likely elsewhere (fuse, switch, wiring). If it's not turning, it likely needs replacement.
4. The Wiper Linkage: The linkage connecting the motor to the wiper arms could be broken, rusted, or seized. Inspect the linkage for any obvious damage or binding. Lubrication might help if it's just stiff, but replacement parts might be needed for more significant problems.
5. The Wiper Arms: Though less likely to cause complete failure, the wiper arms themselves could be loose or improperly attached to the motor shaft, preventing them from working correctly. Check that they are securely fastened.
6. Wiring and Connections: Corrosion or damaged wiring can interrupt the electrical circuit. Inspect the wiring harness leading to the motor and switch for any breaks, loose connections, or signs of corrosion. Clean connections and repair or replace damaged wiring as needed.
7. Park Switch (if applicable): Some wiper systems use a park switch to ensure the wipers stop in the parked position. A faulty park switch could prevent the wipers from operating.
Troubleshooting Steps:
1. Start with the simplest: Check the fuses first. This is the easiest and cheapest fix.
2. Visual Inspection: Look for obvious damage to the wiper motor, linkage, arms, and wiring.
3. Check for Power: Use a multimeter to check for power at the wiper motor. If no power is present, trace the circuit back to identify the problem.
4. Test the Switch: Try wiggling the switch to see if it's faulty.
5. Consult a Repair Manual: A repair manual specific to your 1979 Chevy Impala will provide detailed diagrams and instructions for troubleshooting the wiper system.
If you're not comfortable working on electrical systems or mechanical components, it's best to take your Impala to a qualified mechanic. Finding replacement parts for a classic car might require searching specialty parts suppliers.
