- Start the engine.
- Activate the rear window defogger system.
- Connect a test lamp to a good ground.
Important: The test lamp brilliance will decrease proportionately to the increased
resistance in the grid line as the probe is moved from the battery positive
bus wire to the ground bus wire. The test lamp brilliance may vary from one
window to another.
- Move the test lamp probe from zone 5 to zone 1 along each grid line.
• | If the test lamp shows full brilliance at both ends of the grid
lines. Inspect for an open or poor connection in the ground circuit of the
rear window defogger grid. Refer to
Circuit Testing
and
Wiring Repairs
in Wiring Systems. |
• | If the test lamp goes out, test the grid
line in at least 2 places ((1) and (3)) to eliminate the possibility of bridging
the open (2) in the grid line. |
- Once the open (2) is located, repair the grid line. Refer to
Grid Line Repair
.