* Worn-out wiper motor: The motor itself might be failing. It may not have the power to complete the full sweep. This is a common cause of intermittent or incomplete wiper operation.
* Worn-out wiper motor linkage: The linkage connecting the motor to the wiper arms can become worn, rusted, or broken. This prevents the arms from moving through their full range of motion. This is especially likely on a car of that age.
* Bad wiper switch: The switch itself might be faulty, sending an incomplete signal to the motor, causing it to stop prematurely.
* Wiring issues: Broken, corroded, or loose wires in the wiper motor circuit can interrupt the power supply and cause the wipers to stop short. Check the connections at the motor and switch.
* Park position issue: The mechanism that parks the wipers might be malfunctioning, causing them to stop prematurely instead of completing the sweep and parking correctly.
* Binding: The wiper arms might be binding due to dirt, debris, or old, cracked wiper blades. Try cleaning the arms and replacing the blades. Make sure there's nothing interfering with the wiper arms' movement.
* Low voltage: While less likely, a consistently low voltage in the car's electrical system could also cause the motor to struggle and stop before completing its sweep.
Troubleshooting Steps:
1. Inspect the wiper blades and arms: Check for debris, cracks, or binding. Replace blades if needed.
2. Check the wiper motor: Listen for unusual noises. A grinding or clicking sound indicates a problem. Visually inspect the motor for any obvious damage.
3. Examine the wiper linkage: Look for any signs of wear, rust, or breakage.
4. Check the wiring: Inspect the wires connecting the wiper motor and switch for damage or corrosion.
5. Test the wiper switch: Try the different wiper speeds. A faulty switch could be the culprit.
6. Check the fuses: Check the relevant fuses in the fuse box.
If you're not comfortable working on the car yourself, it's best to take it to a mechanic for diagnosis and repair. The age of the vehicle makes it more likely that multiple components are involved, making proper diagnosis more difficult for someone without experience.
