Rear Window Defogger Switch, Checking Heating Functions

From 7/92

NOTE:

From 7/92, switch terminal -3- is protected by a 10 amp wire link fuse.

The wire link fuse cannot be replaced individually.

Heated mirror function, checking

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-- Remove rear window defogger switch.

-- Depress switch to ON.

-- Using multimeter (Fluke 83 or equivalent), set to measure resistance (Ω), connect test leads between switch terminals -5- and -3-.

Must read approx. 0.5 ohms (Ω)

If NOT, wire link fuse or switch is faulty:

-- Replace switch.

Rear window defogger function, checking

-- Remove rear window defogger switch.

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-- Depress switch to ON.

-- Using multimeter (Fluke 83 or equivalent), set to measure resistance (Ω), connect test leads between switch terminals -5- and -6-.

Must read approx. 0.5 ohms (Ω)

If NOT:

-- Replace switch.

Vehicles with A/C

NOTE:

After the rear window defogger switch is switched on, the heating function lasts for 10 minutes before automatically switching off. The mirror heating is via switch terminal -3- and rear window defogging via switch terminal -6-.

-- Remove switch.

-- Using multimeter (Fluke 83 or equivalent), set to measure resistance (Ω), connect test leads between switch terminals -6- and -3-

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Must read approx. 0.5 ohms (Ω)

If NOT, wire link is faulty:

-- Replace switch.