System Description

WARNING: This page is about a different car, the 2005 Nissan 350Z. 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 supplied at all times

through 20A fuse [No. 75 and 80, located in the IPDM E/R]
to rear window defogger relay terminal 3 and 6.
through 40A fusible link (letter F, located in the fuse and fusible link box)
to BCM terminal 55.
through 10A fuse [No. 18, located in the fuse block (J/B)]
to BCM terminal 42.
through 10A fuse [No. 19, located in the fuse block (J/B)]
to unified meter and A/C amp. terminal 21.

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 38.
through 10A fuse [No. 12, located in the fuse block (J/B)]
to unified meter and A/C amp. terminal 22 and rear window defogger relay terminal 1
and then through unified meter and A/C amp.
to A/C controller (rear window defogger switch) terminal 72 and 84.

Ground is supplied

to BCM terminal 52
through body grounds M30, and M66.
to unified meter and A/C amp. terminal 29 and 30
through body grounds M30 and M66.
to internal CPU of IPDM E/R terminal 38 and 60
through body grounds E17, E43 and F152.

When A/C controller (rear window defogger switch) is turned ON, Rear window defogger switch signals are transmitted,

through A/C controller terminal 87
to unified meter and A/C amp.

Then ground is supplied

to BCM terminal 9
through unified meter and A/C amp. terminal 38
through unified meter and A/C amp. terminal 30
through body grounds M30 and M66.

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

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

When IPDM E/R receives rear window defogger switch signals,

Ground is supplied

to rear window defogger relay terminal 2
through IPDM E/R terminal 52
through internal CPU of IPDM E/R
through IPDM E/R terminal 60
through body grounds E17, E43 and F152, and then rear window defogger relay is energized.

When rear window defogger relay is turned ON,

Signals are transmitted

to rear window defogger terminal 1
through rear window defogger relay terminals 5 and 7 (For Coupe)
through rear window defogger relay terminal 5. (For Roadster)

Rear window defogger terminal 2 is grounded through body ground D212. (For Coupe)

Rear window defogger terminal 2 is grounded through body ground B5, B6 and T14. (For Roadster)

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

When rear window defogger relay is turned ON, Power is supplied

through rear window defogger relay terminals 5 and 7 (For Coupe)
through rear window defogger relay terminal 7 (For Roadster)
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.

When rear window defogger relay is turned ON, Power is supplied

through rear window defogger relay terminals 5 and 7 (For Coupe)
through rear window defogger relay terminal 5. (For Roadster)
to unified meter and A/C amp. terminal 56
Then ground is supplied
to A/C controller terminal 78
through unified meter and A/C amp.
through unified meter and A/C amp. terminal 29 and 30
through body grounds M30 and M66.

This energizes rear window defogger indicator.