Section 454 (Window Defogger System): Inspection

WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT OUTER REAR VIEW MIRROR ASSY LH

Apply battery voltage and check operation of the mirror heater.

OK:

MEASUREMENT CONDITION SPECIFICATIONS

Measurement Condition	Specified Condition
Battery positive (+) --> Terminal R39-4 (HTR+) Battery negative (-) --> Terminal R39-12 (HTR-)	Mirror becomes warm

If the result is not as specified, replace the mirror assy.

Fig 1: Applying Battery Voltage And Checking Operation Of Mirror Heater (1 Of 2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT OUTER REAR VIEW MIRROR ASSY RH

Apply battery voltage and check operation of the mirror heater.

OK:

MEASUREMENT CONDITION SPECIFICATIONS

Measurement Condition	Specified Condition
Battery positive (+) --> Terminal R40-4 (HTR+) Battery negative (-) --> Terminal R40-12 (HTR-)	Mirror becomes warm

If the result is not as specified, replace the mirror assy.

Fig 2: Applying Battery Voltage And Checking Operation Of Mirror Heater (2 Of 2)

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 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 3: Wrapping Piece Of Tin Foil Around Tip Of Negative Tester Probe And Press Foil

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	Wire is not broken
Approx. 10 or V	Wire is broken

Fig 4: Checking Voltage At Center Of Each Defogger Wire

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 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.
Slide the positive (+) lead from the battery side to the ground side.
The point where the voltage jumps from approximately 10 V to 0 V is where the defogger wire is broken.

Fig 5: Placing Voltmeter'S Positive (+) Lead Defogger Wire On Battery Side
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

If the defogger wire is not broken, the voltmeter should indicate 0 V at the positive (+) end of the defogger wire but 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 the masking tape along both sides of the wire.
3. Thoroughly mix the repair agent (DuPont paste No. 4817 or equivalent).
  
  Fig 6: 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 7: Applying Small Amount Of Agent To Wire Using Fine Tip Brush
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT RELAY (DEFOG)

Remove the DEFOG relay from the engine room R/B No. 2.

Measure the resistance.

Standard:

TESTER CONDITION SPECIFICATIONS

Tester Condition	Specified Condition
3 - 4	Below 1 Ω
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 8: Measuring Resistance