B1422: Rear Window Defogger Circuit Malfunction

Symptoms

• Rear window heater grid fails to clear frost or condensation
• Defogger button indicator light flashes or fails to turn on

Common causes

• Broken heating grid lines on the rear windshield glass
• Faulty rear defogger relay
• Blown defogger fuse
• Corroded or disconnected wiring tab at the edge of the rear glass

What to do?

Check the defogger fuse and swap the relay to test. Inspect the rear window glass for any visible scratches or breaks in the horizontal metallic grid lines. Use a conductive repair kit to patch any grid line breaks, or re-solder the main electrical lead tab if detached.