System Description

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 only operates for approximately 15 minutes.

Power is supplied at all times

• through 15A fuses (No. 46 and 47, located in the IPDM E/R)
• to rear window defogger relay
• through 10A fuse [No. 8 (with heated mirrors), located in the fuse block (J/B)]
• through 50A fusible link (letter j, located in the fuse and fusible link box)
• to BCM terminal 70.

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

• through ignition relay
• to rear window defogger relay (located in the IPDM E/R)
• through 10A fuse [No. 12, located in the fuse block (J/B)]
• to front air control terminal 2 and
• to BCM terminal 38.

Ground is supplied

• to BCM terminal 67 and
• to front air control terminal 3
• through body grounds M57 and M61
• to IPDM E/R terminals 39 and 59
• through body grounds E9, E15 (all models) and E24 (with MR20DE).

When front air control (rear window defogger switch) is turned to ON, ground is supplied

• to BCM terminal 10
• through front air control terminal 38
• through front air control terminal 3
• through body grounds M57 and M61.

Then rear window defogger switch is illuminated.

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

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

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

• to rear window defogger relay (located in the IPDM E/R)
• through IPDM E/R terminals 39 and 59
• through body grounds E9, E15 (all models) and E24 (with MR20DE).

Then rear window defogger relay is energized.

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 heated mirrors), power is supplied

• to heated mirror relay terminal 1 (with heated mirrors)

Battery power is supplied

• through heated mirror relay terminal 3
• through heated mirror relay terminal 5
• to door mirror (LH and RH) terminal 1.

Ground is supplied

• to heated mirror relay terminal 2
• through body grounds E9, E15 (all models) and E24 (with MR20DE).

Door mirror (LH and RH) is grounded through body grounds M57 and M61.

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