Air Conditioner Not Working
Air conditioning facilitates
the removal of heat from inside the vehicle. The principle applied is that the heat
is removed by the method of conduction and convection. An evaporator which is cold
absorbs the heat from the air that is passed through it and then cold air is forced
out through the vents inside the car by the blower motor. This is done by pressurizing
refrigerant (134a) with a compressor and then releasing refrigerant (134a) inside
the air conditioner evaporator. There are many reasons your air conditioner can
blow warm air. A basic a/c gauge and test light is needed to help diagnose most
air conditioner problems. Always use caution when inspecting an air conditioner
system, a/c systems contain high pressure gas that when released can cause personal
injury. Use all safety precautions.
Troubleshooting Procedure - Basic Checks and Information
Check Serpentine Belt - The air conditioner utilizes a serpentine
belt that supplies power to rotate the compressor, which is basically a refrigerant
pump. If the belt fails the compressor has nothing to drive it, inspect and
replace the belt as
needed to restore operation. If belt is intact proceed to the next step.
Check for Compressor Clutch Engagement - Turn the air conditioner
to the "on" position and set controls to the coldest setting. Start the engine and
allow to idle. Then open the hood and inspect the clutch at the front of the compressor,
is it turning? "Engaged" if so, the system has enough refrigerant to activate. If
the system is low on refrigerant it will not work properly. In this case an air
conditioner recharge kit is needed to recharge the system. If the system is low
on refrigerant it could cycle on and off, making a ticking noise. If the compressor
clutch is not turning proceed to next step.
Air Conditioner Compressor Inspect Fuses - Check under dash panel and under hood power distribution center. Replace failed fuses as needed, recheck system. If the new fuse fails when reinstalled a short circuit is present and requires diagnosing with a wiring schematic, follow circuits to locate short, repair as needed and recheck system.
Fuse Panel with Test Light Inspect for Refrigerant Leaks - If the system has a large leak and no refrigerant remains it will not activate. First test system for a static pressure charge, with the engine off attach an ac gauge to the low side pressure port and check the state of charge. Depending on outside temperature there should be between 50 psi and 80 psi. (Cool and warm).
Air Conditioner Pressure Gauge A refrigerant leak detector is needed to inspect for leak, but if you do not have a leak detector there is an alternative method. The air conditioner system is designed to run with oil suspended in the refrigerant to lubricate the system. Check for oily residue outside the system by inspecting all hoses, compressor, condenser, evaporator or receiver drier and replace any component that has failed.
Leaking Air Conditioner Hose Replace failed parts as required, vacuum system with a vacuum pump and recharge using an air conditioner recharge kit. If system has sufficient refrigerant (134a) proceed to next step. NOTE: Before you replace any a/c component you must evacuate the a/c system of any remaining refrigerant.
Air Conditioner System (appearance may very) Check Temperature Control Vents - The vents inside your car are controlled by a cable, electrical servo or vacuum servo. If the temperature blend door is not functioning properly it will cause warm air from the heater to exit the vents. To check this start the car and allow the engine idle, next turn the blower motor speed on low, switch the temperature control from warm to cold while your ear is close to the vents. You should hear the door move inside the heater box as it swings from open to close. If not, insect for a vacuum leak or a shorted motor in the servo, repair the leak or replace the servo motor. NOTE: Regular Air Conditioner Maintenance Service your a/c system about every two years. Activate your air conditioner system periodically to keep components lubricated. An air conditioner service removes all moisture from the system by creating a vacuum that should be held for at least 30 minutes. Internal system moisture is a leading cause of air conditioner system failure. WARNING! Before air conditioner repair work can be performed the system must be evacuated of all refrigerant or personal injury can occur.
If further technical assistance is needed, our certified car repair technicians are ready to answer your car questions. Related Car Repair Information
Air Conditioner Compressor Inspect Fuses - Check under dash panel and under hood power distribution center. Replace failed fuses as needed, recheck system. If the new fuse fails when reinstalled a short circuit is present and requires diagnosing with a wiring schematic, follow circuits to locate short, repair as needed and recheck system.
Fuse Panel with Test Light Inspect for Refrigerant Leaks - If the system has a large leak and no refrigerant remains it will not activate. First test system for a static pressure charge, with the engine off attach an ac gauge to the low side pressure port and check the state of charge. Depending on outside temperature there should be between 50 psi and 80 psi. (Cool and warm).
Air Conditioner Pressure Gauge A refrigerant leak detector is needed to inspect for leak, but if you do not have a leak detector there is an alternative method. The air conditioner system is designed to run with oil suspended in the refrigerant to lubricate the system. Check for oily residue outside the system by inspecting all hoses, compressor, condenser, evaporator or receiver drier and replace any component that has failed.
Leaking Air Conditioner Hose Replace failed parts as required, vacuum system with a vacuum pump and recharge using an air conditioner recharge kit. If system has sufficient refrigerant (134a) proceed to next step. NOTE: Before you replace any a/c component you must evacuate the a/c system of any remaining refrigerant.
Air Conditioner System (appearance may very) Check Temperature Control Vents - The vents inside your car are controlled by a cable, electrical servo or vacuum servo. If the temperature blend door is not functioning properly it will cause warm air from the heater to exit the vents. To check this start the car and allow the engine idle, next turn the blower motor speed on low, switch the temperature control from warm to cold while your ear is close to the vents. You should hear the door move inside the heater box as it swings from open to close. If not, insect for a vacuum leak or a shorted motor in the servo, repair the leak or replace the servo motor. NOTE: Regular Air Conditioner Maintenance Service your a/c system about every two years. Activate your air conditioner system periodically to keep components lubricated. An air conditioner service removes all moisture from the system by creating a vacuum that should be held for at least 30 minutes. Internal system moisture is a leading cause of air conditioner system failure. WARNING! Before air conditioner repair work can be performed the system must be evacuated of all refrigerant or personal injury can occur.
If further technical assistance is needed, our certified car repair technicians are ready to answer your car questions. Related Car Repair Information