Rear Window Defroster Filament Inspection

1. Turn the ignition switch to the ON position.
2. Turn the rear window defroster switch on.
   CAUTION:

   • Directly touching the rear window defroster filament with the lead of the voltmeter could damage it. Wrap aluminum foil around the end of the lead and test the rear window defroster filament by touching it with the foil.
   Fig 1: Touching Rear Window Defroster Filament With Lead Of Voltmeter

   Courtesy of MAZDA MOTORS CORP.
3. Connect the positive lead of the tester to the positive side of each rear window defroster filament and the negative lead to ground.
4. Gradually slide the positive lead from the positive side to the negative side and verify that the voltage decreases accordingly.

• If the voltage changes rapidly, the rear window defroster filament has a malfunction. Repair the rear window defroster filament.

VOLTAGE (REFERENCE)

Measured part	Voltage (Reference)
(1) to (2)	Approx. 12 V to 0 V

Fig 2: Checking Voltage Drop In Filament

Courtesy of MAZDA MOTORS CORP.