Nissan Maxima Service and Repair Manual: Rear window defogger system

System Diagram

System Description

Operation Description

• When rear window defogger switch is turned ON while ignition switch is ON, the A/C auto amp. (rear window defogger switch) transmits rear window defogger switch signal to BCM.
• BCM turns rear window defogger relay ON when rear window defogger switch signal is received.
• Rear window defogger and door mirror defogger (with door mirror defogger) are supplied with power and operate when rear window defogger relay turns ON.
• Rear window defogger ON is displayed when controller (A/C auto amp.) receives signals.

Timer function

• BCM turns rear window defogger relay ON for approximately 15 minutes when rear window defogger switch is turned ON while ignition switch is ON. It makes rear window defogger and door mirror defogger (with door mirror defogger) operate.
• Timer is canceled after pressing rear window defogger switch again during timer operation. Then BCM turns rear window defogger relay OFF. The same reaction also occurs during timer operation, if the ignition switch is turned OFF.

INPUT/OUTPUT SIGNAL CHART

*: With door mirror defogger

Component Parts Location

1. BCM M16, M17, M18, M19 (view with instrument panel removed)
2. A. Fuse block (J/B)
   B. Rear window defogger relay J-2
3. A/C auto amp. (rear window defogger switch) M37
4. Door mirror (door mirror defogger) LH D4, RH D107 (if equipped)
5. A. Rear window defogger B53
   B. Condenser B52 (view with rear pillar finisher LH removed)
6. Rear window defogger B54 (view with rear pillar finisher RH removed)

Component Description

BCM	Operates the rear window defogger with the operation of rear window defogger switch. Performs the timer control of rear window defogger.
Rear window defogger relay	Operates the rear window defogger and the door mirror defogger with the control signal from BCM.
A/C auto amp. (rear window defogger switch)	The rear window defogger switch is turned ON. Turns the indicator lamp ON when detecting the operation of rear window defogger
Rear window defogger	Heats the heating wire with the power supply from the rear window defogger relay to prevent the rear window from fogging up.
Door mirror defogger*	Heats the heating wire with the power supply from the rear window defogger relay to prevent the door mirror from fogging up.

*: With heated mirrors