A/C System Initial Inspection
The initial inspection of the air conditioning system is performed after the customers complaints and concerns have been reviewed. Troubleshooting and inspection starts during the test drive and is completed after the vehicle has been pulled into the technicians bay. The first thing and start of any diagnostic procedure is to verify the customers complaint.
While driving the vehicle notice the operation of the air conditioning system and verify any concerns the customer is experiencing. Check blower motor operation and the various speeds the blower motor offers. Listen and observe engine operation while the compressors clutch is cycling and any strange or clicking noises coming from inside the dash area.
If the compressors clutch was unheard during the initial test drive make sure it is observed in operation in the service bay. Observing the compressors clutch in operation is a sure indication that the compressors electrical and control system is functioning. Also notice fan speed operation. A weak or inoperative fan will leave the condenser will little or no air flow deeply effecting the condensers ability to cool and condense the incoming refrigerant. Visually inspect all hoses and connections for oil spots. Oil on a hose or connection must be checked, this is often an indication of a leak in the system.
No matter how well the air conditioning system operates, if the blend doors are mixing heated air with the cooled air the system will perform poorly. The blend door or temperature door is used to blend the heated air from the heater core with the chilled air leaving the evaporator core. The temperature at the outlet tube of the evaporator should be cool to the touch because this tube is on the low side of the system after the systems metering device.
With a manual air control the operator can block any air from passing through the heater core with MAX AC or block all air from passing through the evaporator for the full heat position. The operator can also achieve any variable setting in between. An automated computer controlled system will adjust the blend door to the temperature entered into the control head by the vehicles operator.
