Diesel Data: Automotive Repair

Rear Blower Motor

CIRCUIT OPERATION
When the rear blower relay energizes, circuit C40 supplies battery voltage to the rear blower motor. At LOW and MEDIUM speeds, ground for the rear blower motor passes through the temperature sensor and one or more resistors, depending on speed selection.

Two switches operate the rear blower motor by supplying ground; the front control switch and the rear control switch. The front control switch must be in the ON position for the rear control switch to operate the rear blower motor.