Chad’s Finicky Air Conditioner

So Chad’s air conditioning fan has a mind of its own – the temperature of the air it blows out depends on its mood. Sometimes the passenger side works, while the driver’s side is in a funk. And, there have been times when the fan turns on full blast in the dead of winter?! Frustrating eh? Lets take a look.

The air conditioning system has four parts through which refrigerant flows:
a mechanical compressor, driven by the vehicle’s engine;
an expansion valve, which is a restriction the compressor pumps against; and
two heat exchangers: the evaporator and the condenser.

If the AC compressor clicks on and off, and the accumulator feels cold, then hot air blowing out is usually caused by a failing or failed Blend Door Actuator, located deep in the dash and attached to the hot/cold blend door. It would need to be replaced.

If no air is coming from air conditioning vents then any combination or all of the following may apply:
1. the air conditioner fuse may need to be replaced.
2. the air conditioner system may be discharged, so it would need to be evacuated, charged and leak tested by an MVAC certified technician.
3. the Air conditioner low pressure switch or fan resistor pack may be defective and require replacing.
4. there may be loose connection, broken wiring or defective air conditioner relay in the air conditioning electrical circuit.

If warm air is blowing out, then the following may be the issue:
1. Air conditioner system is discharged, so it would need to be evacuated, charged and leak tested by an MVAC certified technician.
2. The air conditioner compressor clutch may not be not engaging due to faulty wiring, electrical connections and compressor clutch.
3. If, the a/c lines going into the firewall are cold, then the Electronic Blend Door Actuator may need replacing.