Testing Rear Window Defogger Grid Lines
- Place the ignition in the RUN position and turn on the defogger
system.
 
- Ground a J 35616-200 
 test
lamp and lightly touch the prod tip to each grid line.
 
- Move the J 35616-200 
 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 J 35616-200 
 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.