Test all of the grid lines in at least 2 places in order to eliminate the possibility of bridging a break. Test each grid line a few millimeters from the center of the window.
If abnormal test lamp brilliance is apparent on a specific grid line complete the following steps:
Decreasing brilliance of the test lamp indicates a break in the continuity of the grid line. Refer to Rear Window Defogger Inoperative or Defoggers and Heated Mirrors Always On for the electrical diagnosis of the rear window defogger system.
