On-Vehicle Inspection

INSPECT BACK DOOR GLASS (DEFOGGER WIRE)

Turn the ignition switch ON.
Turn the defogger switch ON.

Check the voltage.

Using a voltmeter, measure the voltage at the center of each defogger wire as shown in the illustration.

Standard

VOLTAGE SPECIFICATIONS

Voltage	Condition
Approximately 5 V	Wire not broken
Approximately 10 or 0 V	Wire broken

NOTE: When measuring the voltage, wrap a piece of tin foil around the tip of the negative tester probe and press the foil against the wire with your finger, as shown in the illustration.

HINT:

If there is approximately 10 V, the wire may be faulty between the center of the wire and the battery. If there is no voltage, the wire may be faulty between the center of the wire and the ground.

Fig 1: Measuring Voltage At Center Of Each Defogger Wire

Place the positive (+) voltmeter probe against the defogger wire on the battery side.
Place the foil strip on the negative (-) voltmeter probe against the wire on the ground side.
Slide the positive (+) probe from the battery side to the ground side.
The point where the voltage drops from approximately 10 V to 0 V is where the defogger wire is broken.
HINT:

If the defogger wire is not broken, the voltmeter should indicate 0 V at the positive (+) end of the defogger wire but the indicated voltage gradually increases to approximately 12 V as the meter probe moves toward the other end.

Fig 2: Checking Voltage Between Center Of Defogger Wire
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT REAR WINDOW DEFOGGER
1. Check the operation.
2. Check that the indicator illuminates and the rear window defogger becomes warm when the rear defogger switch is pressed.
3. Check that the indicator turns off and the rear window defogger operation terminates after approximately 15 minutes.