Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Window Defogger Wire

On-vehicle Inspection

ON-VEHICLE INSPECTION

PROCEDURE

1. CHECK REAR WINDOW DEFOGGER OPERATION

(a) When the engine switch is ON and the rear window defogger switch is pressed, check that the window defogger system operates.

2. INSPECT BACK DOOR GLASS (REAR WINDOW DEFOGGER WIRE)

(a) Turn the engine switch to ON (IG).

*1 Rear Window Defogger Wire *a Tester Probe *b Tin Foil

(b) Turn the rear window defogger switch on.

(c) Measure the voltage at the center of each rear window defogger wire to check the wire as shown in the illustration. Result: Voltage Criteria 4 to 6 V Wire is not broken 11 to 14 V Wire is broken between the center and ground side end Below 1 V Wire is broken between the center and battery side end HINT: If the voltage is 11 to 14 V, the wire may be broken between the center of the wire and the wire end on the ground side. If the voltage is below 1 V, the wire may be broken between the center of the wire and the wire end on the battery side.

*a Foil Strip *b Center of Wire

(d) Place the positive (+) lead of the voltmeter against the rear window defogger wire on the battery side.

*a 11 to 14 V *b Below 1 V *c Ground Side *d Battery Side *e Foil Strip *f Broken Wire

(e) Place the negative (-) lead of the voltmeter with the foil strip against the wire on the ground side.

(f) Slide the positive (+) lead from the battery side to the ground side. The point where the voltage drops to below 1 V from 11 to 14 V is the place where the rear window defogger wire is broken.

HINT:

If the rear window defogger wire is not broken, the voltmeter should indicate 11 to 14 V at the battery side. As the positive (+) lead is moved to the ground side, the voltage gradually decreases to below 1 V.

Repair

REPAIR

PROCEDURE

1. REPAIR BACK DOOR GLASS (REAR WINDOW DEFOGGER WIRE)

(a) Clean the broken wire tips with a grease, wax and silicone remover.

(b) Place masking tape along both sides of the wire.

(c) Thoroughly mix the repair agent (Dupont paste No. 4817 or equivalent).

(d) Using a fine tip brush, apply a small amount of the agent to the wire.

(e) After a few minutes, remove the masking tape.

NOTICE:

Do not use the rear window defogger for at least 24 hours after performing the repair.