The purpose of the cycling switch in a cycling clutch system is to control the evaporator temperature above the freezing point by controlling the the operation of the a/c compressor clutch. Based on pressure input from the low side of the a/c system the cycling switch will open power to the a/c compressor clutch coil when the pressure/temperature is so low that could cause the evaporator to freeze up. Once the pressure/temperature has stabilized the cycling switch closes its contacts again allowing power to the air conditioning compressor clutch coil and compressor operation is allowed until it lowers the pressure/temperature near the evaporator freezing point, where the cycle repeats again.
Thermal switches are used on both the low and high side of AC systems. A Thermal switch may be connected in series with the compressor clutch.
A/C compressor cycling control .
A thermostatic switch de-energizes the clutch and stops the compressor to keep the evaporator from freezing up. When the temperature of the evaporator approaches the freezing point (or the low setting of the switch), the thermostatic switch opens the circuit and disengages the compressor clutch. The compressor remains inoperative until the evaporator temperature rises to the preset temperature, at which time the switch closes and compressor operation resumes.
A/C Compressor temperature control.
A thermal limit switch may be mounted on or near the compressor and is used to stop compressor operation before the temperature of the compressor reaches a point of damage.
The air delivery system controls the movement of heated and cooled air into and throughout the passenger compartment. The Hvac housing is the plenum unit located and beneath the instrument panel. It contains the evaporator, heater core, the blower motor assembly, blower speed control device and the vacuum controlled door actuators.
The plenum houses the air doors and door actuators that direct airflow to the correct ductwork. The doors may be controlled by cables, vacuum, or electrical actuators. Single zone systems are usually equipped with three doors.
AC vacuum-controlled door actuator main fault
Automotive ac climate control panel levers may operate a rotary switch to select the various vacuum or air routings to the motors that control A/C modes. The main fault experienced with vacuum-controlled door actuators is vacuum leaks.
Do you need assistance with the ac vacuum-controlled door in your vehicle?
We have auto ac mechanics in your area in Miami-Dade County. Some ac door actuators may be located underneath the dashboard of the vehicle and to get access to them could be labor intensive. Give Us a Call Today!