Blower & A/C Controls (Manual)
CIRCUIT DESCRIPTIONBlower Control
When the ignition switch in ON, battery voltage is applied to the coil of the blower relay. With blower switch in any position except OFF, ground is provided to the coil of the blower relay through the blower switch. Battery voltage is then applied to the blower motor through the closed contacts of the blower relay, ground is provided to the blower motor through blower resistor and blower switch for the desired blower motor speed. As the blower switch is moved from OFF to position 4, resistors in the resistor block are bypassed. Decreasing the resistance will increase the current applied to the blower motor. This increases the blower motor speed.
When the fan switch is in position 4, all of the resistors are bypassed.
The maximum current is now applied to the blower motor so that it runs at the highest speed.
A/C Control
With the ignition switch in ON, battery voltage is applied to the coil of the blower relay from fuse 12. With the blower switch in any position except OFF, ground is provided to the coil of the blower relay through the blower switch. With the A/C switch in ON, the PCM will ground the coil of the A/C relay after a short delay to adjust idle speed. Battery voltage will then be applied to the magnetic clutch of the compressor from A/C compressor fuse, to make the A/C compressor run.