Manual

CIRCUIT DESCRIPTION

Blower control

With the ignition switch in ON and the blower switch in any position except OFF, the blower relay coil energizes and the blower relay contact closes. Battery voltage is then applied to the blower motor through the closed contacts of the blower relay and then ground is provided to the blower motor through the blower resistor and the blower switch. As the blower switch is moved from OFF to HI, resistance of the resistors (built in to the blower resistor) will decrease and battery voltage applied to the blower motor will increase. This will increase the blower motor speed. When the blower switch is in HI, all of the resistors are by passed and the maximum voltage is now applied to the blower motor so that it runs at the highest speed.

A/C control

With the ignition switch in ON and the blower switch in any position except OFF, the blower relay coil energizes and the blower relay contact closes. Battery voltage is then applied to the blower motor through the closed contacts of the blower relay and then ground is provided to the blower motor through the blower resistor and the blower switch. Battery voltage is applied to A/C switch through the fuse 15. With the A/C switch in ON, the Engine Control Module (ECM) will ground the coil of the A/C control relay after a short delay to adjust idle speed. Battery voltage will then be applied to the compressor magnetic clutch from the A/C fuse through the closed contacts of the A/C relay. The A/C compressor runs. Refer to the shop manual, section HA for details.