1. Check the Fuse: Locate the fuse box in your 2004 Toyota and identify the fuse responsible for the rear window defroster. Check if the fuse is blown. If it is, replace it with a fuse of the same amperage.
2. Inspect Wiring: Look for any loose, damaged, or corroded wiring connecting the rear window defroster to the power source. Check the wiring harness and connectors for any issues.
3. Test the Defroster Grid: Use a multimeter to test the continuity of the defroster grid. Ensure that the grid is intact and there are no breaks or disconnections.
4. Check the Defroster Relay: The rear window defroster relay controls the power supply to the defroster grid. Locate the relay and check if it is functioning properly. Replace the relay if necessary.
5. Examine the Defroster Switch: Ensure that the defroster switch is in the "On" position and is not faulty. Clean or replace the switch if needed.
6. Check the Ground Connection: Verify that the ground connection for the rear window defroster is secure and free from any rust or corrosion. Clean or repair the ground connection as required.
7. Consult the Owner's Manual: Refer to the owner's manual for your specific 2004 Toyota model to check if there are any specific instructions or troubleshooting steps for the rear window defroster.
If you are unable to resolve the issue by following these steps, it is recommended to take your vehicle to a qualified mechanic or an authorized Toyota dealership for further diagnosis and repair.
