Checking the heater relay
1. Check for continuous conductivity between terminals "1" and "2" of the relay.
2. Check for continuity between terminals "1" and "2" of the relay when applying battery voltage between terminals "3" and "5". If the continuity does not match the description, replace the relay.
Checking and repairing rear window defroster wires
Note.
- When cleaning the glass, use a soft, dry cloth, wipe the glass parallel to the heater wires. Try not to damage the wires.
- It is prohibited to use detergents and compounds containing abrasive particles.
- When measuring voltage, wrap the negative terminal of the tester with foil and press the edge of the foil to the wire with your finger.
1. Checking for broken wires.
a) Turn on the ignition and the rear window heater.
b) Measure the voltage at the center of each thermocouple wire as shown in the figure.
c) If the voltage is about 5V, then the wire is normal.
d) If the voltage is about 10 V, then there is a break in the wire between the middle and the side bus (+) of the thermoelement.
d) If the voltage is about 0 V, then there is a break in the wire between the middle and the ground.
2. Finding the location of the break in the wire.
a) Connect the "plus" of the voltmeter to the side bus (+) of the thermocouple
b) Wrap the "minus" of the voltmeter with foil. Connect the foil to the thermocouple wire at the side bus (+) and slowly move it to the opposite end (to "ground").
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c) The point at which the voltmeter needle deviates from zero by several volts is the break point.
Note: If there is no wire break, the voltmeter will show 0 V at the side bus (+) of the thermocouple and, when the voltmeter contact is moved to the opposite end of the wire, the voltage will gradually increase to approximately 12 V.
3. Repair of wires.
a) Clean the ends of the wire at the break point with solvent and stick protective tape on both sides of the wire.
b) Mix the repair compound thoroughly and apply a drop of the substance to the wire using a fine-tipped brush.
Repair compound: DUPONT PASTE No.4817 or similar substance.
c) After a few minutes, remove the protective tape and leave to harden for 24 hours.