Defogger System: Inspection

INSPECT DEFOGGER RELAY

Inspect the defogger relay (marking: DEF) continuity. Standard:

TERMINAL SPECIFICATION

Terminal No.	Condition	Specified condition
1<=>2	Constant	Continuity
3<=>5	Constant	No continuity
3<=>5	Apply B+ between terminals 1 and 2	Continuity

If the continuity is not as specified, replace the relay. 2.

Fig 1: Identifying Defogger Relay

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT BACK WINDOW (DEFOGGER WIRE)

NOTE:

When cleaning the glass, wipe the glass along the wire using a soft and dry cloth. Take care not to damage the wires.
Do not use detergents or glass cleaners including abrasive ingredients.
When measuring 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.

Fig 2: Inspecting Back Window

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Check the voltage at the center of each defogger wire, as shown in the illustration.

Standard:

VOLTAGE CRITERIA

Voltage	Criteria
Approx. 5 V	Okay, wire is not broken
Approx. 10 V or 0 V	Wire is broken

HINT:

If there is approx 10 V, the wire may be broken between the center of the wire and the end on the battery side. If there is no voltage, the wire may be broken between the center of the wire and the end on the ground side.

Fig 3: Measuring Voltage At Center

Place the voltmeter positive (+) lead against the defogger wire on the battery side.
Place the voltmeter negative (-) lead with the foil strip against the wire on the ground side.

Fig 4: Measuring Voltage Center Of Wire & End On Battery Side
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Slide the positive (+) lead from the battery side to the ground side.
The point where the voltmeter deflects from approx 10 V to 0 V is the place where the defogger wire is broken.
HINT:

If the defogger wire is not broken, the voltmeter indicates 0 V at the positive (+) end of the defogger wire but gradually increases to approx 12 V as the meter probe moves to the other end.

Fig 5: Inspecting Defogger
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
If necessary, repair the defogger wire.
1. Clean the broken wire tips with grease, wax and silicone remover.
2. Place the masking tape along both sides of the wire.
3. Thoroughly mix the repair agent (DuPont paste No. 4817).
4. Using a fine tip brush, apply a small amount of the agent to the wire.
5. After a few minutes, remove the masking tape.

NOTE: Do not repair the defogger wire again for at least 24 hours.

Fig 6: Using Fine Tip Brush