1. Fuses: Check the fuse box (usually under the hood or inside the cabin) for a blown fuse related to the rear wiper. Your owner's manual will show you the fuse layout and which fuse controls the rear wiper.
2. Relay: The rear wiper often uses a relay to switch the higher current needed to operate the motor. A faulty relay can prevent the wiper from functioning. You might need to test the relay with a multimeter or replace it as a test.
3. Wiper Motor: The motor itself could be faulty. This is a more involved issue requiring either replacement or professional diagnosis to determine if it's the motor or its wiring. You might hear a clicking sound if the motor is getting power but failing to turn.
4. Wiring and Connections: Check the wiring harness leading to the motor for any breaks, corrosion, or loose connections. This includes the connector at the motor itself and any connectors along the harness. Pay close attention to areas that might be prone to wear and tear (e.g., where the wiring bends near the hinge).
5. Switch: The rear wiper switch itself could be malfunctioning. Try cleaning the switch contacts with contact cleaner (if accessible) or replace the switch if necessary.
6. Ground: A poor ground connection can prevent the motor from receiving sufficient power. Inspect the ground wire connected to the wiper motor and chassis. Make sure the connection is clean and tight.
7. Wiper Arm and Linkage: While less likely to cause a complete failure, a seized or broken wiper arm or linkage could prevent the wiper blade from moving. Visually inspect these components for any obvious problems.
Troubleshooting Steps:
1. Start with the simplest: Check the fuse first. This is the easiest and quickest thing to do.
2. Visual Inspection: Look for obvious problems with the wiring, motor, arm, and linkage.
3. Test the Relay: If the fuse is good, test or replace the relay.
4. Check the Switch: See if the switch is functioning correctly (though this is less likely to be the sole cause of complete failure).
5. Advanced Diagnostics: If the above steps don't solve the problem, you may need a multimeter to check voltage at the motor, relay, and switch to pinpoint the fault. This requires some electrical knowledge.
If you're not comfortable working with car electrical systems, it's best to take your Isuzu Rodeo to a qualified mechanic for diagnosis and repair. Attempting repairs without the proper knowledge and tools can lead to further damage.
