Electronic

Blower Motor speed is determined by the amount of voltage applied to the motor. This voltage varies from approximately 4 volts (low speed) to approximately 12 volts (high speed).
The speed at which the Blower Motor operates is governed by the Electronic A/C Control Assembly. The Blower Motor speed can be adjusted manually by pressing the blower control "UP" or "DOWN" switches or automatically by placing the Electronic A/C Control Assembly in the "AUTO" mode.
The Electronic A/C Control Assembly sends blower request information to the Electronic A/C Power Module in the form of a variable voltage signal. This voltage signal ranges from approximately 2.5 volts, for minimum blower speed, to approximately 7 volts, for maximum blower speed. An amplifier and driver circuit in the Electronic A/C Power Module supplies between 4 and 12 volts to the Blower Motor according to the request signal from the Electronic A/C Control Assembly. Blower Motor voltage is also sent back to the Electronic A/C Control Assembly to insure blower speed stability and to indicate any failure in the Blower Motor circuitry.