A/C and Heat: Heating, Ventilation, Air Conditioning (HVAC) Service & Repair

Your air conditioning system is part of your HVAC (heating, ventilation, and air conditioning) system, and one of the key components in your vehicle’s comfort-control center.  When your air conditioning is not functioning properly, driving can be miserable and, in some cases, even dangerous.   All modern cars have a heater, and most have an air conditioner.  These components help maintain safe and comfortable driving conditions, including visibility.

HVAC System

The HVAC System provides proper in vehicle climate conditions.  It de-humidifies the vehicle interior (and helps to clear fogged windshields).  You must seal and contain refrigerant, lubricant, and coolant.

Symptoms of a malfunctioning HVAC System

  • Improper vent air temperature
  • Low or no vent air flow
  • Smell or fogging of windshield during defroster operation
  • Growling/grinding or squealing noise during A/C or heater operation
  • Overheating

Air Conditioning (A/C)


Component Information

A/C Compressor

  • Refrigerant Pump
  • May contain control valves for A/C pressure control
  • Controlled by On-Board Computer
  • Must be lubricated internally


  • Allows heat removed from passenger compartment to be transferred tot he under hood area.

Condenser/Radiator Fan

  • Assists in removing heat generated by proper condenser and radiator operation.
  • Electrically or hydraulically controlled
  • Controlled by On-Board Computer

Receiver/Dryer or Accumulator

  • Stores liquid refrigerant
  • Removes moisture from flowing refrigerant (desiccant)

Blower Fan

  • Moves air inside vehicle across evaporator and/or heater core
  • Electric Motor
  • Controlled by climate control panel

Expansion Valve/orifice tube

  • Creates pressure differential allowing refrigerant to remove heat from passenger compartment
  • Thermostatic or fixed orifice design


  • Allows heat to be removed via refrigerant from the passenger’s compartment to be carried to the condenser


  • Substance that can be vaporized and condensed between certain temperatures
  • Must be kept pure and free of contaminates and moisture
  • 134a is approved refrigerant for today’s vehicles

Are there environmental concerns with air conditioning?

Because all refrigerants currently used in automotive air conditioning systems are controlled substances, it is important that it not be allowed to escape into the atmosphere during servicing.  Our technicians use a sealed, environmentally-friendly process that captures the refrigerant, cleans it, replenishes it and returns it to your auto air conditioning system good as new.

What if my vehicle still uses Freon?

Auto air conditioning systems built before 1995 use the refrigerant R-12 or (CFC-12), also referred to as Freon. The EPA determined that Freon was destroying the ozone layer and in 1995, all production ceased. Freon is now extremely expensive and difficult to find. Precision Tune Auto Care offers a retrofit service that enables your A/C system to use R-134a refrigerant. The retrofit pays for itself in the cost savings on the refrigerant.  Consult your local store manager for more information on retrofitting.


Component Information


  • Transfers heat from coolant to outside air
  • Constructed of aluminum, steel, or composite plastics

Radiator/Heater Hoses

  • Provides convenient transfer and routing of coolant to heater core
  • Constructed of reinforced rubber compounds

Blower Fan

  • Moves air inside vehicle across evaporator and/or heater core
  • Electric Motor
  • Controlled by climate control panel


  • Regulates flow of coolant
  • Allows vehicle to reach and maintain proper operating temperature
  • Proper operation allows sufficient heat for passenger comfort

Heater Core/Heater Control Valve

  • Heat exchanger located inside passenger compartment
  • Contains hot engine coolant which allows proper temperatures to be maintained in passenger compartment
  • Similar construction to radiator
  • Control valve regulates coolant flow to heater core

Not all PTAC centers provide this service. To see what services each center provides and to find the nearest center close to you, please click here.