Defogger System - Diagnostics: Inspection

INSPECT REAR 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 Fig 1.

Fig 1: Wrapping Piece Of Tin Foil Around Tip Of Negative Tester Probe & Pressing Foil Against 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 Fig 2.

Standard:

CENTER OF EACH DEFOGGER WIRE

Voltage	Specified Condition
Approx. 5 V	Wire is not broken
Approx. 10 or 0 V	Wire is broken

Fig 2: Measuring 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 3: Placing Voltmeter's Positive (+) Lead Against 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. The voltage gradually increases to approximately 12 V as the lead 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.
  
  Fig 4: Placing Masking Tape Along Both Sides Of Wires
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Thoroughly mix the repair agent (Dupont paste No. 4817 or equivalent).
4. Using a fine tip brush, apply a small amount of the agent to the wire.
  
  Fig 5: Applying Small Amount Of Agent To Wire Using Tip Brush
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. After a few minutes, remove the masking tape.
NOTE: Do not repair the defogger wire again for at least 24 hours.