1. Park Position Switch/Mechanism:
* Problem: This is the most likely culprit. The mechanism that tells the wipers to park (return to their resting position) is failing. This could be a worn-out switch within the motor itself, a broken linkage connecting the motor to the wiper arms, or a problem with the motor's internal park gear.
* Troubleshooting: Try gently moving the wiper arms by hand to see if they're mechanically obstructed. If they move freely, the problem is likely electrical or within the motor. If they're stiff or bound, you might have a linkage issue (lubrication or a broken part).
2. Wiper Motor:
* Problem: The motor itself might be failing. The internal components responsible for parking may be worn or damaged.
* Troubleshooting: This requires more investigation. You might hear unusual noises (grinding, clicking) from the motor when you try to activate the wipers. A failing motor often exhibits erratic wiping patterns before completely failing.
3. Wiring and Electrical Connections:
* Problem: A loose or corroded connection in the wiring leading to the wiper motor, or a fault in the wiper switch stalk itself, could prevent the parking signal from reaching the motor correctly.
* Troubleshooting: Inspect the wiring harness connected to the wiper motor for any damage, corrosion, or loose connections. You'll likely need to consult a wiring diagram for your specific Impala model to trace the wires.
4. Wiper Motor Control Module (if equipped):
* Problem: Some vehicles have a separate control module for the wipers. This module could be faulty and preventing the wipers from parking. This is less likely in a 2002 Impala, but possible.
* Troubleshooting: Diagnosing this requires more advanced tools and testing beyond basic DIY capabilities.
What to Do:
1. Safety First: Disconnect the negative battery terminal before attempting any repairs involving the wiper motor or electrical system.
2. Visual Inspection: Carefully examine the wiper linkage and motor for any obvious damage, broken parts, or loose connections. Lubricate moving parts (if needed) with a suitable lubricant (like silicone spray).
3. Testing (Requires multimeter): If you're comfortable with basic electrical testing, you can use a multimeter to check the voltage reaching the wiper motor. However, this step is more advanced and requires some electrical knowledge.
4. Professional Help: If you're not comfortable with electrical work or mechanical repair, it's best to take your Impala to a qualified mechanic. They have the tools and experience to diagnose and fix the problem efficiently. Replacing the wiper motor is a common repair, but the specific repair will depend on the actual fault.
Replacing the Wiper Motor (if necessary): This is a moderately difficult repair requiring some mechanical aptitude. You'll likely need to access the motor under the hood (often behind the cowl), disconnect the electrical connectors and linkage, and install the new motor. Consult a repair manual specific to your 2002 Chevy Impala for detailed instructions.
Replacing the wiper motor is usually the most common solution for this problem. Remember to always disconnect the battery's negative terminal before working on the car's electrical system.
