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