Air Temperature Actuators

When the HVAC system is in the OFF mode, pressing any HVAC switch, except the passenger temperature switch, will enable the automatic HVAC system. If the HVAC control module displays any temperature between 19-29°C (66-84°F), turning the temperature switch will increase/decrease the set temperature by 1°. If the temperature setting is 30°C (85°F), turning the temperature switch up increases the set temperature to 32°C (90°F).

The left air temperature actuator is an electronic stepper motor with feedback potentiometers. 0 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 processor, 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 processor to the solid state circuit. The HVAC control processor software uses this reference voltage to determine the left air temperature actuator position through the left air temperature door position signal circuit. The motor opens the left air temperature actuator 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. 0 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 processor, 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 processor to the solid state circuit. The HVAC control processor software uses this reference voltage to determine the right air temperature actuator position through the right air temperature door position signal circuit. The motor opens the air mixture door to a position to divert sufficient air past the heater core or evaporator to achieve the desired vehicle temperature.