- Start the engine.
- Activate the rear window defogger system.
- Ground one test lamp lead.
- Connect the other test lamp lead to each of the grid lines at
points 1 through 5 as shown in the figure.
Specification: Normal Test Lamp Brilliance
| • | Section number 1 -- No Bulb Brilliance |
| • | Section number 2 - 1/4 Bulb Brilliance |
| • | Section number 3 - 1/2 Bulb Brilliance |
| • | Section number 4 - 3/4 Bulb Brilliance |
| • | Section number 5 -- Full Bulb Brilliance |
Important: The lamp brilliance will decrease proportionately to the increased resistance
in the grid line as the probe is moved from the feed bus wire to the ground
bus wire. Test all of the grid lines in at least two places in order
to eliminate the possibility of bridging a break. The range of test
lamp brilliance may vary from one window to another.
- Compare the test lamp brilliance pattern with the normal test
lamp brilliance in order to check for proper grid operation:
| • | If the test lamp shows full brilliance at both ends of the grid
lines, inspect for a loose ground wire contact to body ground. |
| • | If an abnormal lamp reading is apparent on a specific grid line,
place the test lamp lead on that grid at the feed bus bar and move the lead
toward the ground bus bar until the lamp goes out. This will indicate
the location of the break. |
