Circuit/System Description

For an overview of the component/system, refer to Rear Window Defogger Description and Operation

Circuit	Description
B+ - Relay Switch	Supplied from a fuse.
E18 Rear Defogger GridControl - Component	The output circuit is switched to 12 V to activate the component.
Control - Relay Coil	The output circuit is switched to 12 V to activate the component.
E18 Rear Defogger GridGround - Component	Chassis Ground
Ground - Relay Coil	Chassis Ground

Component	Description
X53A Fuse Block - Rear Body	The fuse block houses various fuses and relays.
E18 Rear Defogger Grid	Window defoggers are parallel resistive conductors in or on the glass that heat up when electric power is applied.
K33 HVAC Control Module	The control module controls a series of actuators to ensure optimal heating, ventilation and air conditioning of the passenger compartment. The control module does this by reading values from a variety of sensors and interprets the data and adjusts the actuators accordingly.
A26 HVAC Controls	The position of the defogger switch is read by the control module A26 and, via CAN bus, forwarded to the control module K33, which translates the bus message into a control signal for E18.