7B-8 Air Conditioning System: Manual Type
A/C System Performance Inspection
1) Confirm that vehicle and environmental conditions
are as follows.
• Vehicle is put indoors.
• Ambient temperature is within 25 – 35 °C (77 – 95
• Relative humidity is within 30 – 70%.
• There is no wind indoors.
• HVAC unit is normal.
• Blower motor is normal.
• There is no air leakage from air ducts.
• Condenser fins are clean.
• HVAC air filter is not clogged with dirt and dust (if
• Battery voltage is about 12 V.
• Radiator cooling fan operates normally.
2) Make sure that high pressure valve (1) and low
pressure valve (2) of manifold gauge are firmly
3) Connect high pressure charging hose (3) to high
pressure service valve (5) on vehicle and low
pressure charging hose (4) to low pressure service
4) Bleed the air in charging hoses (3) and (4) by
loosening their nuts respectively utilizing the
refrigerant pressure. When a hissing sound is heard,
immediately tighten nut.
Do not connect high and low pressure
charging hoses in reverse.
Diagnostic Information and Procedures
5) Warm up engine to the normal operating
temperature and keep it at the specified idle speed.
6) Turn A/C switch ON, set blower speed selector at
maximum speed position, temperature selector at
maximum cold position, air flow selector at face
position, and air intake selector at recirculation
position. (Confirm that A/C compressor, A/C
condenser cooling fan and radiator cooling fan are
7) Wait for ten minutes to stabilize the A/C operation.
8) Open all door windows, front doors and engine hood.
9) With about 20 mm (0.8 in.) of dry bulb thermometer
(1) put right in front of center ventilation louver and a
wet and dry bulb thermometer (2) near air inlet of