Air Temperature Actuator

The temperature actuator is a 3-wire bi-directional electric motor. Ignition 3 voltage, ground and control circuit enable the actuator to operate. The control circuit uses a zero-12 volt linear-ramped signal to command the actuator movement. The zero and 12 volt control values represent the opposite limits of the actuator range of motion. The values in between zero-12 volts correspond to the positions between the limits.

When the HVAC control module sets a commanded, or targeted, value, the control signal is set to a value between zero-12 volts. The actuator shaft rotates until the commanded position is reached. The module will maintain the control value until a new commanded value is needed. When full cold is selected, a low voltage, near ground, is applied to control circuit. When full hot is selected, a high voltage, 12 volts, is applied to the control circuit.