Ram air flowing through the evaporator does not provide enough air flow inside the vehicle for cooling purposes. So, a blower is used to force the air along. An electric motor spins a fan, forcing the air into ducts, which direct it to the particular vent selected by the operator.
If the blower motor gets full voltage, it will run at high speed, but that is not always desirable. Therefore resistors are used to cut the speed down. The fan switch directs the current flow through one or more resistors to achieve the slow and medium speeds.
Inputs that may affect A/C clutch operation include (but are not limited
If these sensor and switch values are either above or below the
programmed operating range, the compressor clutch may not engage
Depending on the vehicle, additional items that may affect compressor
operation could include:
and low pressure cut-out switches
clutch cycling switch
Refrigerant leaks .
There are two types of refrigerant leaks in the automotive
air conditioning system: Active leaks and Passive leaks.
active refrigerant leak is a continuous leak. It doesn’t matter if the
engine or ac system in your car is off or on hot or cold the refrigerant
continuously leaks out
passive refrigerant leak is a type of leak the intermittently occurs. They
are really hard to find, because technicians should recreate the same
conditions of pressure, temperature or vibration for the leak to happen.
The receiver drier is a storage tank for the liquid refrigerant from the condenser. It also contains a bag of desiccant.
The purpose of the desiccant is to absorb any moisture that might enter the system during assembly or service. The receiver drier is often neglected when the air conditioning system is serviced or repaired.Failure to replace it can lead to poor system performance or replacement part failure.
When should I change my AC filter drier?
It is recommended that the receiver drier and /or its desiccant be changed whenever a component is replaced, the system has lost the refrigerant charge, or the system has been open to the atmosphere for any length of time.
AC receiver drier refrigerant flow restriction.
If the receiver-drier outlet is colder than the inlet, this unit is restricted and should be changed to restore efficient and proper system operation.
A vehicle that is stopped stalls when the steering wheel is turned to full lock only when the air conditioning is on.
The power steering pressure switch signals the computer to increase the engine idle speed during parking-type maneuvers. If the vehicle has a bad power steering pressure switch, the engine could stall at idle when the steering is moved to the full lock position. This is due to increased load on the engine from the power steering pump.
When the fins and air passages of an evaporator are clogged with dirt, air will have a difficult time passing through the evaporator. Since the principles of air conditioning require the heated air around the evaporator to lose heat, a vehicle with a clogged evaporator will have poor A/C performance.
Evaporator core maintenance.
The evaporator core should be removed from the case to properly clean it. Airborne debris, such as leaves, lint, hair, and other contaminants, enters the evaporator case and clings to the wet evaporator core.
The A/C drainage.
The drain is for the purpose of removing the condensation that forms as a result of humidity being removed from the intake air. It is nearly impossible to adequately clean an evaporator core without first removing it from the case.