For 1990-2009 cars only
Testing Rear Window Defogger Grid Lines
- Place the ignition in the RUN position and turn on the defogger system.
- Ground a test lamp and lightly touch the prod tip to each grid line.
- Move the test lamp from the feed wire side of each grid. The lamp will begin bright and gradually dim as the lamp is moved across the grid. Ensure that you inspect each grid line in at least 2 places to avoid the possibility of bridging a gap.
- Inspect for loose ground wire connections to the sheet metal, when the test lamp shows full brilliance at both ends of the grid line.
- A break is located when the lamp suddenly goes out as the lamp moves across the grid.
