Manual HVAC

Blower Controls

The blower motor is controlled by the heater control panel which receives battery voltage at all times through fuse 18. With the ignition switch in ACC (I) or ON (II), battery voltage is supplied to the heater control panel through fuse 16. The heater control panel is grounded at G404.

Battery voltage is applied through fuse 12 to the blower motor relay contacts at all times. With the ignition switch in ACC (I) or ON (II) and the engine not cranking, the blower motor relay in the under-hood fuse/relay box is energized which feeds battery voltage to the blower motor. The blower power transistor controls the blower motor in all speeds except HIGH. The blower power transistor is controlled by the heater control panel. When the heater control panel requests HIGH blower speed, it grounds the blower motor through the contacts of the blower motor high relay, making the blower run at high speed.

Refer to the HVAC system for specific tests or troubleshooting procedures.