Component Tests and General Diagnostics

1. INSPECT DEFOGGER SWITCH CONTINUITY
If continuity is not as specified, replace the switch.







2. INSPECT INSTRUMENT PANEL JUNCTION BLOCK CIRCUIT (Rear Defogger Relay)
a. Remove the instrument panel junction block.
b. Inspect the "A" connector on the instrument panel junction block back side, as shown in the chart.
c. Disconnect the "B" connector from the instrument panel junction block and inspect the connectors on the wire harness side, as shown in the chart.
If circuit is as specified, try replacing the relay with a new one. If the circuit is not as specified, inspect the circuit connected to other parts.




3. INSPECT INSTRUMENT PANEL JUNCTION BLOCK OPERATION (Rear Defogger Relay)
a. Connect the positive (+) lead from the voltmeter to terminal C7 and the negative (-) lead to body ground.
b. Connect the negative (-) lead from the body ground to terminal A5.
If continuity is not as specified, replace the instrument panel junction block.

4. INSPECT DEFOGGER WIRE






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 the 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 finger, as shown.

a. Turn the ignition switch ON.
b. Turn the defogger switch ON.




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

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.




d. Place the voltmeter positive (+) lead against the defogger positive (+) terminal.
e. 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.
f. 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 probe moves to the other end.

5. IF NECESSARY,REPAIR DEFOGGER WIRE




a. Clean the broken wire tips with grease, wax and silicone remover.
b. Place the masking tape along both sides of the wire to be repaired.
c. Thoroughly mix the repair agent (Dupont paste No.4817).




d. Using a fine tip brush, apply a small amount to the wire.
e. After a few minutes, remove the masking tape.
f. Do not repair the defogger wire for at least 24 hours.