Repairing the Condenser

• The truck's A/C compressor is the heart of the unit. Compressors have a certain volume of refrigerant, the additive responsible for effective extracting head from surrounding air. Compressing the refrigerant drives down its temperature (makes it colder) and as it gets colder extracts the heat from air circulated about the coolant. Check the coolant levels in the A/C unit and refill with the correct refrigerant if needed. Older trucks (more than 20 years), may require a refrigerant no longer available to the public. Check the owner's manual or look on the side of the compressor for refrigerant specifications. If your truck does need older refrigerant, a certified vehicle A/C technician must service it. These professionals are the only mechanics allowed today to handle these older materials. Repairing a compressor, however, usually involves replacement. Fortunately, A/C compressors are attached by screws and bolts with no welding or other attachments.
  
  Removing the compressor and installing a new one is just a matter of unbolting the mounts, disconnecting refrigerant inlet and outlet fittings and completing the reverse process for installation. Make sure, though, to bleed all the refrigerant before disconnecting the refrigerant fittings. Refrigerant is under pressure. Located on the refrigerant tubing is a small outlet valve similar to a tire valve. Depress it until the refrigerant is expelled.
  
  

Repair the Drive Belt

• A flywheel in the main serpentine drive belt drives the air conditioner compressor. This belt is on the front of the engine and winds around other flywheels driving the oil, water, power brake and steering (if equipped) pumps and on some models the radiator fan. If the belt is slipping, the compressor does not spin continuously and warm A/C air may be the first sign the belt needs replacing before larger problems happen (pump failure, engine overheating, etc.). Check the serpentine belt for wear. If there is any slack or fraying of the belt, replace immediately. Loosen the belt tension wheel with a fitting socket to remove and install the belt. There will be a diagram on the front of the motor for the proper winding to get all the flywheels attached to the belt.
  
  

Repair the fan

• A fan behind the dashboard drives the cold air through the vents. Depending on your truck model, the fan could be directly behind, underneath and behind on the other side of the firewall (the sheet metal separating the engine bay from the cab). Locate the fan and make sure it operates as specified. If the blade is broken, replace the fan. If the fan blade unit is loose from the fan drive shaft, tighten with the appropriate tool. Make sure the fan is free of any dirt buildup, grease or oil. Fans should run clean and without lubrication.
  
  

Repair the Thermostat Controls

• Start by making sure the fuse for the A/C unit is working properly. If the A/C will not turn on with or without the fuse, the fuse needs to be replaced. Also, check inside the dashboard for any loose or broken connections. Repair as needed. Finally, remove and install a new unit if the temperature control unit will not respond to any settings. This requires no soldering as all connections are done with screws. So taking out the old and putting in a new temperature control unit is not difficult.