Air Temperature Actuator

When the HVAC system is in the OFF mode, toggling the left air temperature switch will actuate the automatic HVAC system. If the HVAC control module displays any set temperatures between 16-30°C (60-90°F), toggling the temperature switch will increase/decrease the set temperature by 1 degree. The I/P fuse block provides power to the left and right air temperature actuators through the ignition 3 voltage circuit. Ground is provided by the low reference circuit and HVAC control module.

The air temperature actuators are electronic stepper motors with feedback potentiometers. The left air temperature door position signal circuit sends a voltage signal to the actuator requesting a desired temperature. Zero volts drives the actuator in one direction while 5 volts moves the actuator in the opposite direction. When the actuator receives 2.5 volts, actuator rotation stops. A 5-volt reference signal is sent out over the 5-volt reference circuit, from the HVAC control module, to the left air temperature actuator. When a desired temperature setting is selected, whether manual or automatic, the solid state circuit is used to determine the left air temperature door position sensor signals value. A separate 5-volt reference is sent from the HVAC control module to the solid state circuit. The HVAC control module software uses this reference voltage to determine the left air temperature actuator position through the left air temperature door position circuit. The motor opens the air mixture door to a position to divert sufficient air past the heater core to achieve the desired vehicle temperature.

The right air temperature actuator operates the same as the left side. The right air temperature door position signal circuit sends a voltage signal to the actuator requesting a desired temperature. Zero volts drives the actuator in one direction while 5 volts moves the actuator in the opposite direction. When the actuator receives 2.5 volts, actuator rotation stops. A 5-volt reference signal is sent out over the 5-volt reference circuit, from the HVAC control module, to the right air temperature actuator. When a desired temperature setting is selected, whether manual or automatic, the solid state circuit is used to determine the right air temperature door position sensor signals value. A separate 5-volt reference is sent from the HVAC control module to the solid state circuit. The HVAC control module software uses this reference voltage to determine the right air temperature actuator position through the right air temperature door position circuit. The motor opens the air mixture door to a position to divert sufficient air past the heater core to achieve the desired vehicle temperature.