System Description

WARNING: This page is about a different car, the 2003 Infiniti G35. 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 IPDM E/R (Intelligent Power Distribution Module Engine Room).

The rear window defogger operates only for approximately 15 minutes.

Power is at all times supplied.

through 20A fuse [No. 77, and 78, located in the IPDM E/R]
to rear window defogger relay terminal 3 and 6.
through 10A fuse [No. 21, located in the fuse block (J/B)]
to rear window defogger relay terminal 1.
through 50A fusible link [letter F , located in the fuse block (J/B)]
to BCM terminal 7.

With the ignition switch turned to ON or START position.

Power is supplied

through 10A fuse [No. 1, located in the fuse block (J/B)]
to BCM terminal 35.
through 10A fuse [No. 12, located in the fuse block (J/B)]
to A/C and audio controller terminal 2.

Ground is supplied

to BCM terminal 8
through body grounds E17, and E43.
to A/C and audio controller terminal 3
through body grounds M30 and M66.
to internal CPU of IPDM E/R terminal 14 and 45
through body grounds E17, and E43.

When A/C and audio controller (rear window defogger switch) is turned to ON, Ground is supplied

to BCM terminal 69
through A/C and audio controller terminal 12
through A/C and audio controller terminal 3
through body grounds M30 and M66.

Then BCM recognizes that rear window defogger switch is turned to ON.

Then rear window defogger switch is illuminated.

Then it sends rear window defogger switch signals to IPDM E/R via DATA LINE (CAN-H, CAN-L).

When IPDM receives rear window defogger switch signals.

Ground is supplied

to rear window defogger relay terminal 2
through IPDM E/R terminal 54
through internal CPU of IPDM E/R and IPDM E/R terminal 45
through body grounds E17 and E43.

and then rear window defogger relay is energized.

When rear window defogger relay is turned ON,

Power is supplied

through rear window defogger relay terminals 5
to rear window defogger terminal 2

rear window defogger terminal 1, is grounded through body ground B452.

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

When rear window defogger relay is turned to ON (with mirror defogger models),

Power is supplied

through rear window defogger relay terminals 5 and 7,
through fuse block (J/B) terminal 2C,
through 10A fuse [No. 8, located in the fuse block (J/B)],
through fuse block (J/B) terminal 5B.
to door mirror defogger (Driver side and passenger side) terminal 2.

Door mirror defogger (Driver side and passenger side) terminal 1 is grounded through body grounds M30 and M66.

With power and ground supplied, door mirror defogger filaments heat and defog the mirror.