System Description

WARNING: This page is about a different car, the 2005 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. 75, and 80, located in the IPDM E/R]
To rear window defogger relay terminal 3 and 6
Through 10A fuse [No. 18, located in the fuse block (J/B)]
To BCM terminal 42.
Through 50A fusible link [letter F , located in the fuse block (J/B)]
To BCM terminal 55.

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 rear window defogger relay terminal 1, and
To A/C and audio controller terminal 2.

With the ignition switch turned to ACC or ON position, Power is supplied

Through 10A fuse [No. 6, located in the fuse block (J/B)]
To BCM terminal 11.

Ground is supplied

To BCM terminal 52
Through body grounds M30, and M66.
To A/C and audio controller terminal 3
Through body grounds M30 and M66.
To internal CPU of IPDM E/R terminal 38 and 60
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 9
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 52
Through internal CPU of IPDM E/R and IPDM E/R terminal 60
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 and 7
To rear window defogger terminal 2

rear window defogger terminal 1, is grounded through body ground B242.

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

When rear window defogger relay is turned to ON,

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.