System Testing
- Start engine. Press rear window defogger on. Indicator light should illuminate. If light does not illuminate on vehicles with Manual Temperature Control (MTC), see REAR WINDOW DEFOGGER RELAY TEST . If light does not illuminate on vehicles with Automatic Temperature Control (ATC), see ATC TEST 1A: REAR WINDOW DEFOGGER MALFUNCTION under SCAN TOOL TESTING. If light illuminates, go to next step.
- Using a voltmeter with negative lead connected to ground, touch positive lead to point "A" (driver side). See Fig 1 . If no voltage is present, go to FUSE & ELECTRICAL SHORT TEST . If voltage is more than 11 volts, press rear window defogger switch off. Voltage should be zero volts. If voltage is as specified, go to GRID FILAMENT TEST .
NOTE:
Indicator light illumination does not confirm system operation. It only indicates that power is available at relay output.