For 1990-2009 cars only
Testing Rear Window Defogger Grid Lines
- Start the engine and turn on the defogger system.
- Ground a test lamp and lightly touch the prod tip to each grid line.
- Move the 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 in order to avoid the possibility of bridging a gap.
- Inspect for a loose ground wire connection 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 you move the lamp across the grid.
