The rear window defogger system consists of the following major components:

1. A tinted glass
2. Ceramic, silver compound element grid lines on the glass
3. Two bus bars that are baked onto the inside of the glass
4. The feed wire (terminal), soldered to the LH of the bus bar
5. The ground wire (terminal), soldered to the RH of the bus bar

The rear window defogger system operates on 12 volts. Under some conditions, the heat on the window may not be obvious to the touch. The length of time required to remove interior fog from the rear window will vary with the following factors:

1. The vehicle speed
2. The outside window temperature
3. The atmospheric pressure
4. The number of passengers

Press the rear window defogger switch on the I/P in order to turn the defogger on. The defogger automatically turns off after 10 minutes or immediately after pressing the switch for a second time.

HVAC Manual (C60)

With the Ignition Switch in RUN, the RR DEFOG mini relay #44 coil and the HVAC control head receive B+ from the HVAC Mini fuse #18. Activating the rear defogger switch applies voltage momentarily to the solid state timer. The timer sends a rear defogger request signal from the control head to the body control module (BCM). Upon receiving this signal, the BCM energizes the relay. The relay then applies B+ from the RR DEFOG maxifuse #46 to the defogger grid.

The initial defog cycle lasts ten minutes. Any subsequent defog request will activate the grid for 5 minutes. Cycling the ignition will reset the sequence. Pressing the switch during any defog cycle will remove the request signal to the BCM and the relay will de-energize.

HVAC Automatic (CJ2)

The operation of the rear window is the same as with C60 except that the HVAC programmer module sends the request signal to the BCM via the Class 2 serial data circuitry.

Heated Mirrors

Heated mirrors are only available with RPO CJ2. The mirrors operate in combination with the rear window defogger. The BCM sends the request for heated mirrors on the serial data circuits to each door control module. These modules then supply voltage and ground to the mirror heating elements for the duration of the defog cycle. Removing the request signal deactivates the heating elements.