Heated Glass Element: Description and Operation

System Description
The rear window defogger system is controlled by the smart entrance control unit. The rear window defogger operates only for approximately 15 minutes.

Power is supplied at all times to rear window defogger relay terminal 3 through 20 A fuse (No.7, located in the fuse and fusible link box) and to rear window defogger relay terminal 6 through 20 A fuse (No.4, located in the fuse and fusible link box). To the smart entrance control unit terminal 49 through 10 A fuse (No.13, located in the fuse and fusible link box).

With the ignition switch in the ON or START position, power is supplied through 10 A fuse [No.10, located in the fuse block (J/B)] to the rear window defogger relay terminal 1 and to the smart entrance control unit terminal 27.

Ground is supplied to terminal 32 (with auto A/C) or 17 (with manual A/C) of the rear defogger switch (built-in A/C control unit or A/C auto amp.) through body grounds M9, M25 and M87.

When the rear defogger switch is turned ON, ground is supplied through terminal 31 (with auto A/C) or 9 (with manual A/C) of the rear defogger switch to the smart entrance control unit terminal 14.

Terminal 37 of the smart entrance control unit then supplies ground to the rear window defogger relay terminal 2.
With power and ground supplied, the rear window defogger relay is energized.

Power is supplied through terminals 5 and 7 of the rear window defogger relay to the rear window defogger.

The rear window defogger has an independent ground.

With power and ground supplied, the rear window defogger filaments heat and defog the rear window.

When the system is activated, the rear window defogger indicator illuminates in the rear window defogger
switch.