Basic System (HVAC): Other Mazda Tribute I рестайлинг

Manual A/C

The manual climate control system heats or cools the vehicle interior depending on the position of the function selector switch and the temperature selected. The position of the function selector switch determines heating or cooling and air distribution. The temperature control setting determines air temperature.

The manual climate control system components include

1. Blower motor switch resistor
2. Vacuum reservoir tank
3. Climate control assembly
4. Blower motor relay
5. A/C compressor clutch relay
6. Footwell vent vacuum control motor
7. Defrost vacuum control motor
8. Panel vent vacuum control motor
9. Outside air inlet vacuum control motor
10. Temperature blend door control cable

Scheme 95

The climate control assembly has three system controls

1. The A/C heater function selector switch combines a vacuum selector valve with two electrical switches to supply battery positive voltage (B+) to the A/C clutch circuit and the blower motor control circuit.
2. The temperature selection is accomplished through cable-controlled positioning of the temperature blend door located in the heater core housing.
3. The blower motor switch controls the blower motor speed by adding or bypassing resistors in the heater blower motor switch resistor.

Scheme 96

The four-speed operation of the blower motor is achieved through the blower motor switch resistor and contains a thermal limiter which is used as a temperature protecting fuse. The assembly is located on the passenger-side on the evaporator core housing behind the glove compartment.

Blower Motor Relay

The blower motor relay supplies voltage to the blower motor and is activated when the key is ON and the function selector switch is in any position besides OFF. The blower motor relay is located under the instrument panel next to the steering column.

A/C Compressor Clutch Relay

The A/C compressor clutch relay supplies voltage to the A/C compressor clutch and is located in the battery junction box (BJB). The power control module (PCM) can interrupt the A/C compressor operation through the A/C compressor clutch relay under the following conditions

1. During engine start-up
2. Wide open throttle (WOT)
3. Low engine idle conditions
4. Excessively high engine temperatures

AIR DISTRIBUTION

There are two sources of air available to the air distribution system

1. Outside air
2. Recirculated air

Air distribution within the vehicle is determined by the function selector switch position. Air flow control doors are used to direct air flow within the A/C evaporator housing (if equipped) and heater. Vacuum control motors are used to position these air flow control doors. See CLIMATE CONTROL SYSTEM , for description and operation of each of the system functions.

The air distribution system is designed to provide airflow from the defrost nozzle when no vacuum is applied to any of the vacuum control motors. This is done to prevent a situation where defrost cannot be obtained due to a system vacuum leak.

Air enters the passenger compartment from the

1. Instrument panel register
2. Heater outlet floor duct
3. Windshield defroster hose nozzle
4. Side window demisters
5. Rear footwell duct

Passenger compartment air is exhausted from the vehicle through open windows or through the air extractors located in the rear of the vehicle.

HEATING AND VENTILATION

The heating and defrosting system has the following features

1. Delivers heated or cooled air (with the A/C option) to maintain the vehicle interior temperature and comfort level.
2. A/C operation (if equipped), reduces the relative humidity of the air inside the vehicle.
3. The blower motor draws outside air or recirculates from within the vehicle air.
4. All air flow from the blower motor passes through the A/C evaporator housing (if equipped).
5. The temperature control door regulates the temperature by blending a varied amount of heated air from the heater core housing and mixing it with the cool air passing through the evaporator housing.

Heater Core Housing

The heater core housing contains the following components

1. Heater core
2. Air temperature control door
3. Panel air flow control door
4. Defrost/floor air flow control door

Scheme 97

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer the heat to air passing through the heater core housing.

Scheme 98

The blower motor pulls air from the air inlet and forces it into the heater core housing where it is mixed and distributed.

HEATER CORE PLUGGED

Note. Testing of returned heater cores reveals that a large percentage of heater cores are good and did not require installation of a new heater core. If a heater core leak is suspected, the heater core must be tested by following the Heater Core Plugged Component Test before the Heater Core Pressure Test, See HEATER CORE PRESSURE TEST . Carry out a system inspection by checking the heater system thoroughly as follows

1. Inspect for evidence of coolant leakage at the heater water hose to heater core attachments. A coolant leak in the heater water hose could follow the heater core tube to the heater core and appear as a leak in the heater core. CAUTION: Spring-type clamps are installed as original equipment. Installation and overtightening of non-specification clamps can cause leakage at the heater water hose connection and damage the heater core.
2. Check the integrity of the heater water hose clamps. WARNING: The heater core inlet hose will become too hot to handle if the system is working correctly.
3. Check to see that the engine coolant is at the correct level.
4. Start the engine and turn on the heater.
5. When the engine coolant reaches operating temperature, feel the heater core outlet hose to see if it is hot. If it is not hot: The heater core may have an air pocket. The heater core may be plugged, or The thermostat is not working correctly.