Component Description

REFRIGERANT LINE COUPLER - FRONT
Spring-lock type refrigerant Tine couplers are used to connect many of the refrigerant hues and other components to the refrigerant system. These couplers require a special tool for disengaging the two coupler halves.

Fig. 4 Spring-Lock Coupler - Typical:

The spring-lock coupler is held together by a garter spring inside a circular cage on the male half of the fitting. When the two coupler halves are connected, the flared end of the female fitting slips behind the garter spring inside the cage on the male fitting. The garter spring and cage prevent the flared end of the female fitting from pulling out of the cage.

Two O-rings on the male half of the fitting are used to seal the connection. These O-rings are compatible with R-134a refrigerant and must be replaced with O-rings made of the same material.

Secondary clips are installed over the two connected coupler halves at the factory for added blowoff protection.

ELECTRIC COOLANT PUMP - FRONT
The electric coolant pump is used on all vehicles. The pump is located under the hood on the right inner fender well.

The pump is controlled by the HVAC controller and is only operational under the following conditions:
1. Vehicle speed below 17 m.p.h.
2. Coolant temperature above 150° but less than 230 °F.
3. Any Blower speed setting.
4. Temperature heat setting above the halfway setting (60% heat).
5. The pump will turn off at speeds above 30 m.p.h.
6. If the coolant temperature rises above 230 °F.

PLUMBING - REAR
Spring-lock refrigerant line couplers are used to connect many of the refrigerant lines and other components to the refrigerant system. These couplers require a special tool for disengaging the two coupler halves.

High pressures are produced in the refrigerant system when the air conditioning compressor is operating. Extreme care must be exercised to make sure that each of the refrigerant system connections is pressure-tight and leak free. It is a good practice to inspect all flexible hose and metal refrigerant lines at least once a year to make sure they are in good condition and properly routed.

The refrigerant lines and hoses are coupled with other components of the HVAC system with peanut- block style fittings. A stat-O seal type flat steel gasket with a captured compressible O-ring, is used to mate plumbing lines with A/C components to ensure the integrity of the refrigerant system.

The metal refrigerant lines are repairable using a A/C Tube Repair kit such as Kent Moore model J-41425 or equivalent.

REAR EVAPORATOR
The rear evaporator coil is located in the rear heater-A/C unit housing, in the right rear quarter panel. The evaporator coil is positioned in the heater-A/C unit housing so that all air that enters the housing must pass over the fins of the evaporator before it is distributed through the system outlets. However, air passing over the evaporator coil fins will only be conditioned when the compressor is engaged and circulating refrigerant through the evaporator coil tubes.

Refrigerant enters the evaporator from the rear expansion valve as a low-temperature, low pressure mixture of liquid and gas. As air flows over the fins of the evaporator, the humidity in the air condenses on the fins, and the heat from the air is absorbed by the refrigerant. Heat absorption causes the refrigerant to boil and vaporize. The refrigerant becomes a low-pressure gas when it leaves the evaporator. The rear evaporator coil cannot be repaired and, if faulty or damaged, the rear evaporator coil must be replaced.

REAR EXPANSION VALVE
Vehicles equipped with the optional rear A/C unit have an H-type thermal expansion valve (TXV) located on the rear HVAC unit, behind the passenger side rear quarter trim panel. It performs the same function as the front expansion valve, to monitor refrigerant temperature and pressure at the control head and meter the refrigerant entering the evaporator to meet the vehicle cooling requirements.

The rear expansion valve is a factory calibrated unit and cannot be adjusted or repaired. If faulty or damaged, the rear expansion valve unit must be replaced.

REAR HEATER CORE
The rear heater core is located in the heater-A/C housing in the right rear inside quarter panel. It is a heat exchanger made of rows of tubes and fins. The heater core is not repairable and if damaged it must be replaced.

Engine coolant is circulated through heater hoses/tubes to the heater core at all times. As the coolant flows through the heater core, heat removed from the engine is transferred to the heater core fins and tubes. Air directed through the heater core picks up the heat from the heater core fins. The blend air door allows control of the heater output air temperature by controlling how much of the air flowing through the heater-A/C housing is directed through the heater core. The blower motor speed controls the volume of air flowing through the heater-A/C housing. The heater core cannot be repaired and, if faulty or damaged, it must be replaced. Refer to Cooling System for more information on the engine cooling system, the engine coolant and the heater hoses.