how to fix the rear defroster not working in my BMW 3 Series E90/E91 (2005-2012)

Solution

1. Preparation

• Gather necessary tools: multimeter, socket set, flathead screwdriver, and a replacement fuse (if needed).
• Ensure the vehicle is parked on a level surface and is turned off.

2. Inspect and Replace the Fuse

1. Locate the Fuse Box: Open the driver's side door and remove the cover under the dashboard to access the fuse box.
2. Identify the Rear Defroster Fuse: Use the diagram on the fuse box cover to find the correct fuse for the rear defroster.
3. Test the Fuse: Remove the fuse using a fuse puller or pliers and check for continuity with a multimeter.
   • Replace if Blown: If there is no continuity, replace it with a new fuse of the same amperage.
4. Reinstall the Fuse: Place the new or tested fuse back into its slot securely.

3. Inspect the Rear Defroster Grid

1. Visual Inspection: Examine the rear window for any breaks in the defroster grid lines.
2. Repair Grid if Necessary: If breaks are found, use a rear defroster repair kit to restore the conductive grid lines.
   • Follow the kit instructions carefully for application.

4. Test the Rear Defroster

1. Reconnect the Battery: If the battery was disconnected during the repair, reconnect it.
2. Activate the Defroster: Turn on the ignition and press the rear defroster switch.
3. Monitor Functionality: Check for proper operation, ensuring the grid heats up and clears the rear window.