System Description: Notes

WARNING: This page is about a different car, the 2003 Nissan Altima. However, it is still accessible from the selected car via links, so may be relevant.

The rear window defogger system is controlled by BCM (Body Control Module) and rear window defogger relay is controlled by IPDM E/R (Intelligent Power Distribution Module Engine Room). The rear window defogger operates for approximately 15 minutes.

Power is supplied at all times

to rear window defogger relay terminal 3
through 20A fuse (No. 35, located in the IPDM E/R),
to rear window defogger relay terminal 6
through 20A fuse (No. 36, located in the IPDM E/R), and
to BCM terminal 7
through 50A fusible link (letter f , located in the fuse and fusible link box).

With the ignition switch in the ACC or ON position, power is supplied

to BCM terminal 36
through 10A fuse [No. 6, located in the fuse block (J/B)].

With the ignition switch in the ON or START position, power is supplied

through 10A fuse [No. 12, located in the fuse block (J/B)]
to rear window defogger relay terminal 1, and
to BCM terminal 35.

Ground is supplied

to terminals 8, 27 and 63 of the BCM
through body grounds E15, E24, M57 and M61, and
to rear window defogger terminal-
through body ground B202.

With manual A/C, ground is also supplied

to terminals 2 and 4 of the rear window defogger switch
through body grounds M57 and M61.

BCM is connected to IPDM E/R as DATA LINE (CAN H line and CAN L line). When the rear window defogger switch is turned ON, ground is supplied

to BCM terminal 69
through terminal 1 of the rear window defogger switch (with manual A/C), or
through terminal 31 of the A/C auto amplifier (with auto A/C).

BCM outputs rear window defogger switch signal to IPDM E/R via DATA LINE (CAN H line and CAN L line). Ground is then supplied to Terminal 2 of the rear window defogger relay through IPDM E/R terminal 54. 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, and
to terminal 3 of the rear window defogger switch (with manual A/C), or
to terminal 30 of the A/C auto amplifier (with auto A/C).

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.