* Multi-function switch: The most likely culprit is a problem with the wiper motor switch (also called the multi-function switch or stalk). This part controls both wipers and often other functions like turn signals and headlights. A faulty switch can fail to send power to the passenger side motor, even if the driver's side works fine. This is a common point of failure due to wear and tear.
* Wiper motor itself (less likely): While less probable given the driver's side works, a problem within the wiper motor itself could be selectively affecting one side. Internal components like brushes or the motor windings might be failing in such a way as to only impact one wiper arm.
* Wiring harness: A break or short in the wiring harness leading to the passenger-side wiper motor is another possibility. Inspect the wiring for any visible damage, especially near where the harness bends or flexes. Corrosion is also a common issue, particularly in older vehicles.
* Fuse: Check the fuse box for a blown fuse specifically related to the wipers or the passenger-side wiper. It's possible one side has its own fuse, although this is less common.
* Wiper linkage: Although less likely since the driver's side works, there might be a mechanical problem with the linkage connecting the motor to the passenger-side wiper arm. This could involve a broken or dislodged component preventing the arm from moving.
Troubleshooting Steps:
1. Check the fuses: This is the easiest and cheapest step first.
2. Inspect the wiring: Look for breaks, corrosion, or loose connections in the wiring harness leading to the passenger-side wiper motor.
3. Test the multi-function switch: This is often difficult without specialized tools, but a mechanic can usually test its functionality relatively easily.
4. Inspect the wiper linkage: Look for any obvious damage or disconnections in the linkage mechanism.
5. Check the wiper motor itself: This is more involved and often requires removal of the motor for closer inspection.
If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. The cost of a professional diagnosis is usually worth it to avoid spending time and potentially money on unnecessary parts.
