The Mazda pick up truck is manufactured with an optional air-conditioning system which uses circulated freon to cool the interior. This freon is run through several components at high pressure; the condenser, evaporator, and compressor are all critical parts of the air-conditioning system. The average backyard mechanic can repair the AC system in a Mazda truck in about two hours.
Determine the problem with the system by inspecting each component and troubleshooting the issue. A system that blows warm air could be low on freon or have a leak. A system that does not turn on at all might have electrical problems such as a blown fuse or inoperative blower fan. A noisy or chattering system could have a worn out compressor, which is the most common problem.
Evacuate the air-conditioning system by taking the truck to a freon collection facility. Repair shops and some oil change garages will evacuate the system for free, as they get compensated for the amount of freon they collect. It is illegal to vent the system into the atmosphere, and the freon must be collected in authorized equipment. Some garages can also fill the system with a UV sensitive dye, which can be used to locate leaks.
Replace the compressor by pressing firmly onto the tension pulley and working the belt off of the compressor, then unbolting the line and mount bolts that secure the compressor to the engine. Disconnect the wiring harness adapter plug by pulling it from the compressor, then pull the compressor out of the engine bay. Replace the unit with a new compressor by securing the mount and line bolts in a clockwise direction, then pressing the tension pulley to wrap the belt back around the compressor pulley.
Replace the condenser coils by turning the line bolts counterclockwise, then pulling the coil from the plastic pop rivets. The condenser is located in front of the radiator, and looks like a smaller version of the radiator. This part of the system is the source of most freon leaks, as the aluminum coils corrode or the unit becomes damaged from debris. Press the new unit back onto the pop rivets, and reconnect the line bolts in a clockwise direction.
Replace the evaporator by turning the line bolts counterclockwise, then disconnecting the mounting bolts that hold it to the truck body. The evaporator is a cylindrical unit on the passenger side firewall, and can become ice cold when the system is functioning properly. The evaporator can clog with debris, wear out internally or leak (in rare circumstances). Usually replacing the evaporator will correct slow-cooling systems or systems that blow frost or condensation through the vents.
Refill the system with the proper level of freon by attaching the proper valve fitting to the low-pressure nipple in front of the evaporator. This nipple is typically a male adapter that only fits the proper valve. Crank the truck and let the system take in the freon at its own pace, which is usually about 2 lbs. for the 2800 V-6 Mazda engine.
