Automotive Solutions of London on your vehicles climate control.

Description: The air conditioning (A/C) electro-magnetic clutch mounts to the front of the air conditioning compressor and electrically engages and disengages according to commands from the A/C system. Compressor designs may vary from one manufacturer to the next as to internal design and components. The A/C system is divided into two sides: high-pressure and low-pressure. The low-pressure side connects to the inlet of the compressor and the high-pressure side connects to the outlet, or discharge, of the compressor.

Purpose: Upon command, the A/C clutch energizes and locks the clutch to the compressor. Once engaged, a serpentine belt or V-belt from the engine drives the A/C compressor. The compressor’s main job is to pump refrigerant through the system so it can remove heat from the interior of the vehicle. Circulation of refrigerant also provides a secondary benefit -- it moves refrigerant oil throughout the system, providing lubrication to key parts of the system.

Maintenance Tips/Suggestions: Symptoms of a bad compressor or compressor clutch include poor or no cooling, and a noisy or seized compressor. Have your vehicle’s air conditioning system checked yearly by a professional technician. The A/C system also operates when the climate control system is in the defroster mode to remove moisture from the interior, so A/C is more than a summertime creature comfort. Operating an A/C system low on refrigerant not only results in poor cooling, it can also damage the system due to poor lubrication flow. Make sure that the technician servicing your car uses the correct refrigerant and refrigerant oil. Use of the wrong refrigerant or oil can reduce system performance or even cause damage.

Auto Temp Control

Description: Automatic Temperature Control, as its name implies, is an automatic climate control system, which automatically controls interior temperature based on the driver’s demands and temperature information from various sources. ATC does this through direct interaction with the vehicle’s A/C and heating systems. Some ATC systems have separate “zones”, where different temperatures can be maintained according to personal needs. ATC is usually an option, replacing manual heating and air conditioning controls.

Purpose: ATC is largely a convenience option that keeps the interior temperature set to the driver’s preference. ATC also provides some element of additional safety, since the driver needs to spend less time monitoring and setting temperature controls.

Maintenance Tips/Suggestions: ATC directly controls the heating and A/C systems, so most problems thought to be ATC problems really lay in the systems it controls. Regardless of the symptom, have it diagnosed as soon as possible by a professional technician.

A/C Dryer

Description: Although it may go by several different names (filter/dryer, receiver/dryer, or accumulator), the dryer plays a key role in A/C system performance and longevity. The dryer is connected to the A/C refrigerant circuit and looks like a canister made of aluminium, which contains an internal moisture collector called desiccant. A receiver/dryer normally connects to the high side of the system. An accumulator usually connects to the low side of the system. Some systems may use both a receiver/dryer and an accumulator.

Purpose: The A/C dryer removes water and some dirt from the refrigerant and also stores a certain amount of refrigerant as it cycles through the system. Some receiver/dryers have a sight glass mounted on top to aid in charging the A/C system.

Maintenance Tips/Suggestions: An A/C Dryer does not require periodic maintenance. However, the dryer should always be replaced anytime the A/C system is opened for repairs.

A/C Refrigerant

Description: A specially formulated chemical used in the A/C system for exchanging heat. Generally speaking, cars older than 1995 models use R-12 refrigerant, also known as Freon, or CFC-12 (CFC stands for chlorofluorocarbons). R-12 contains chlorine, which depletes the earth’s delicate ozone layer. For this reason, the production and importation of R-12 in Canada was stopped in the 1990s. Cars 1995 and newer use R-134a refrigerant, also sometimes abbreviated as HFC-134a.

Purpose: Removes heat and moisture from the interior of the vehicle and releases it to the outside air. When circulating in the system, refrigerant also helps to move refrigerant oil to key parts throughout the A/C system.

Maintenance Tips/Suggestions: Symptoms of a low refrigerant charge include poor cooling and frequent engagement and disengagement of the A/C compressor. This may also be accompanied by an engine that changes speed with the cycling of the A/C clutch and compressor. A low refrigerant charge can also affect system lubrication, since good refrigerant flow ensures the flow of refrigerant oil. The phase out of R-12 created a hotbed of confusion for motorists due to the introduction of numerous alternative refrigerants. In turn, these alternatives created confusion for technicians, who were then unsure as to whether an alternative was safe, or even legal, for use. Since R-134a has been the standard refrigerant for nearly a decade, issues related to the R-12 phase out have faded away.

Nonetheless, there are some important things to keep in mind if your car needs A/C system service. First, A/C system service costs more than it did in years past. Specialized recovery and recycling equipment, refrigerant identifiers, leak detectors, certification and training, and ongoing changes have increased the cost of A/C service. The threat of cross-contamination, where different types of refrigerants wind up being mixed together, is a nightmare for most technicians and shop owners. That’s why it is wise to seek out a professional technician with a proven track record if your car needs A/C service.

Blower Motor

Description: A variable-speed electric motor connected to a “squirrel-cage” type of fan. The blower motor mounts to a housing surrounding the heater core, evaporator and air control doors.

Purpose: The blower motor moves air from outside the vehicle, through a cabin air filter if equipped, then through the heater core, and/or evaporator based on driver demands. The air control doors control the exact direction of airflow from the blower motor. The resulting airflow then warms or cools the interior, or is used to de-fog or de-ice the windshield.

Maintenance Tips/Suggestions: Symptoms of a blower motor or circuit problem include no airflow when the blower is turned on, a noisy blower motor, or a blower motor that only operates at some speeds. Some blower motor problems may be as simple as a blown fuse (see your owner’s manual) or a bad connection. For best results, have the blower motor circuit checked by a professional technician.

Cabin Air Filter

Description: A filter used to clean incoming air for the car’s HVAC system. Introduced in European vehicles, cabin air filters are now becoming common on more domestic and Asian makes and models. Some examples include the Ford Taurus, Contour, Windstar and Ford trucks; the Chevrolet Impala, Monte Carlo, Suburban, Tahoe and Silverado; and the Lincoln Navigator. Japanese cars such as the Honda Accord and Odyssey, and the Acura RL and TL use cabin filters. To date, approximately 40% of cars have cabin air filters, but the number grows each year.

Purpose: The cabin air filter helps trap pollen, bacteria, dust, and exhaust gases that may find their way into a vehicle’s ventilation system, making the interior of the car a healthier place.

Maintenance Tips/Suggestions: Cabin air filters should be replaced according to owners’ manual guidelines, usually every 15,000 miles. It is not uncommon, however, for cabin air filter replacement to be overlooked in the owner’s manual. Do not try to clean this filter and reinstall it. For best results, consult filter manufacturer application charts to see if your car is listed. Most filters are accessible through an access panel in the HVAC housing, which may be under the hood or in the interior of the car. Some filters require basic hand tools to remove and install the filter; others just require your hands. If neglected, a restricted cabin air filter can impair airflow in the HVAC system, possibly causing interior heating and cooling problems.

Description: A small radiator-like heat exchanger mounted inside the HVAC housing. The heater core has an inlet and outlet that enables coolant flow through the core. A series of tubes and fins provide the surface area for heat exchange.

Purpose: The heater core provides a source of heat for the interior of the vehicle. The driver, using the heater controls and blower motor, controls the exact amount of heat.

Maintenance Tips/Suggestions: The heater core does not require regular maintenance by itself, but is cared for by regular maintenance of the cooling system. This includes coolant changes per the manufacturer’s recommendations. Symptoms of a faulty heater core include coolant on the floor of the interior, a strange smell while the heat is turned on, and poor heater output. Have these symptoms checked out by a qualified technician, who can quickly determine where the fault lies. Problems with a heater core only tend to get worse; so don’t put off having the system checked.

Description: An array of wiring, switches, relays and controls. These components may take on dual roles (both a sensor and a switch), where they turn on certain parts of the circuit based on operating conditions. Increasingly, these circuits and controls are integrated with the vehicle’s powertrain control module (PCM), even on cars without Automatic Temperature Control (ATC).

Purpose: To electrically manage the HVAC system, based on driver demands and vehicle operating conditions. Cars with Automatic Temperature Control (ATC) provide automatic control over HVAC circuits.

Maintenance Tips/Suggestions: Proper HVAC operation requires normal operation of all parts of the control circuits. As an example, a failed temperature switch may cause faulty erratic or no compressor operation, affecting cooling. Problems with HVAC switches and electrical circuits may cause no cooling, poor cooling, excessive cooling, or erratic temperature control. To determine the root cause, have the A/C system looked at by a professional technician.

HVAC Hoses & Valves

Description: High- and low-pressure refrigerant hoses connect the main parts of the air conditioning system together. An orifice tube or thermostatic expansion valve regulates refrigerant flow in the A/C system. Service fittings provide connections for service equipment so that system pressures can be checked and refrigerant may be recovered and recycled. Heater hoses connect the engine’s cooling system to the heater core. A heater control valve may be located in one of the heater hoses to regulate coolant flow to the heater core.

Purpose: Refrigerant hoses provide a path for refrigerant and refrigerant oil between the key components of the A/C system. The orifice tube (most common) or thermostatic expansion valve ensures proper refrigerant flow for different operating conditions. Service fittings, unique for each type of refrigerant, enable the connection of service equipment and reduce the chances of mixing different types of refrigerant. Heater hoses provide a supply and return path for warm engine coolant circulating in the heater core. The heater control valve may help control heater output by opening and closing coolant flow to the heater core.

Maintenance Tips/Suggestions: Hoses and valves should be inspected periodically for condition and to make sure all connections are secure. Chafed, cut or damaged hoses should be replaced. Poor A/C cooling may indicate problems with the orifice or expansion valve. Insufficient heat, or heat that can’t be turned off may indicate a problem with the heater control valve. When in doubt, have your car’s HVAC system evaluated by a qualified professional.

Description: Usually used with Automatic Temperature Control (ATC), there are typically three sensors that sense temperature. One sensor is located on the outside of the car to sense outside air temperature. A second sensor is located in the interior to monitor temperature inside the car. The third sensor is usually located in the HVAC ducting, to sense delivered air temperature.