Section 317 (Defogger System): Inspection

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT DEFOGGER RELAY CONTINUITY

CONNECTOR TERMINALS SPECIFIED CONDITION

Condition	Tester connection	Specified condition
Constant	3 - 4	Continuity
Apply B+ between terminals 3 and 4.	1 - 2	Continuity

If continuity is not as specified, replace the relay.

Fig 1: Inspecting Defogger Relay Continuity

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT DEFOGGER WIRES

NOTE: When cleaning the glass, use a soft, dry cloth, and wipe the glass in the direction of the wire. Take care not to damage wires. Do not use detergents or glass cleaners with abrasive ingredients. When measuring voltage, wind a piece of tin foil around the top of the negative probe and press the foil against the wire with your fingers, as shown.

Fig 2: Pressing Foil Against Wire

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Inspect the voltage at the center of each heat wire, as shown.

VOLTAGE SPECIFICATIONS

Voltage	Criteria
Approx. 5 V	Okay (No break in wire)
Approx. 10 V or 0 V	Broken wire

HINT:

If there is approximately 10 V, the wire is broken between the center of the wire and the positive (+) end. If there is no voltage, the wire is broken between the center of the wire and ground.

Fig 3: Inspecting Defogger Wires (1 Of 2)

Place the voltmeter positive (+) lead against the defogger positive (+) terminal.
Place the voltmeter negative (-) lead with the foil strip against the heat wire at the positive (+) terminal end and slide it toward the negative (-) terminal end.
The point where the voltmeter deflects from zero to several V is the place where the heat wire is broken.
HINT:

If the heat wire is not broken, the voltmeter indicates 0 V at the positive (+) end of the heat wire but gradually increases to about 12 V as the meter robe is moved to the other end.

Fig 4: Inspecting Defogger Wires (2 Of 2)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

IF NECESSARY, REPAIR DEFOGGER WIRE
1. Clean the broken wire tips with a grease, wax and silicone remover.
2. Place the masking tape along both sides of the wire to be repaired.
3. Thoroughly mix the repair agent (Dupont paste No.4817).
  
  Fig 5: Placing Masking Tape Along Both Sides Of Wire
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Using a fine tip brush, apply a small amount to the wire.
5. After a few minutes, remove the masking tape.
6. Allow the repair to stand at least 24 hours.
  
  Fig 6: Applying Small Amount To Wire
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT MIRROR HEATER OPERATION
1. Connect the positive (+) lead from the battery to terminal 4 and the negative (-) lead to terminal 12.
2. Check that the mirror becomes warm.
  HINT:
  
  It will take a short time for the mirror to become warm.
  
  Fig 7: Inspecting Mirror Heater Operation
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002