Window Defogger System: Inspection

INSPECT BACK DOOR GLASS (DEFOGGER WIRE)

NOTE:

When cleaning the glass, wipe the glass along the wire using a soft, dry cloth. Take care not to damage the defogger wires.
Do not use detergents or glass cleaners that have 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 1: Inspecting Back Door Glass (Defogger Wire)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

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

Standard voltage

BACK DOOR GLASS STANDARD VOLTAGE SPECIFICATIONS (DEFOGGER WIRE)

Voltage	Criteria
Approx. 5 V	Wire is not broken
Approx. 10 or 0 V	Wire Is broken

Fig 2: Measuring Voltage At Center Of Defogger Wire

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

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

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

Fig 3: Measuring Voltage At Center Of Defogger Wire
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Slide the positive (+) lead 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 indicates 0 V at the positive (+) end of the defogger wire and gradually increases to approximately 12 V as the meter probe moves to the other end.
If necessary, repair the defogger wire.
1. Clean the broken wire tips with grease, wax and silicone remover.
2. Place masking tape along both sides of the wire.
3. Thoroughly mix the repair agent.
  Dupont paste:
  
  No. 4817 or equivalent
  
  Fig 4: Placing Masking Tape Along Both Sides Of Wire
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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 5: Applying Agent To Wire
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT IG1 RELAY (Marking: IG1)

Remove the IG1 relay from the instrument panel junction block.

Measure the resistance of the relay.

Standard resistance

IG1 RELAY STANDARD RESISTANCE SPECIFICATIONS

Tester Condition	Specified Condition
3-5	10 kΩ or higher
3-5	Below 1 Ω (when battery voltage Is applied to terminals 1 and 2)

If the result is not as specified, replace the relay.

Fig 6: Inspecting IG1 Relay

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (DEF RELAY)

Measure the voltage of the connector.

Standard

INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY TESTER CONNECTION AND SPECIFIED CONDITION REFERENCE (DEF RELAY)

Tester Connection	Defogger Switch Condition	Specified Condition
1F-2- Body ground	OFF	0V
1F-2- Body ground	ON	10 to 14 V

If the result is not as specified, replace the instrument panel junction block assembly.

Fig 7: Identifying Instrument Panel Junction Block Assembly (DEF Relay)