Air Conditioning Troubleshooting
Made Easy!

The following Air Conditioning Troubleshooting methods are for do-it-yourselfers that want to save some money. You will need to have some common sense troubleshooting skills and some basic tools.

When troubleshooting an air conditioner, you need to ask yourself what is the a/c unit suppose to be doing, and what is the a/c unit actually doing? It is only then that you can narrow down the problem.

So we will discuss some common problems, the possible causes for these problems, and the solutions to these problems.

Air Conditioning Troubleshooting

Causes and solutions:

No power- Test for voltage
Loose connections- Tighten connections
Burnt or broken wires- Replace wires
Bad Thermostat- Replace thermostat
Blown Fuse- Replace Fuse
Bad Transformer- Replace transformer

Causes and solutions:

Burnt or broken wires- Replace wires
Bad Thermostat- Replace thermostat
Bad Capacitor- Replace Capacitor
Fan Relay Bad Or Bad Control Board- Replace Fan Relay or Control Board
Fan Motor Bad- Replace Blower Motor
Evaporator iced up- This could be due to a very dirty air filter...if that's your case, replace your air filter, then turn your thermostat to the off position and the fan swith to on, this will help melt the ice. Once the ice is melted (about 4 hours), turn the thermostat back on in the cooling mode, and your good to go. If this is not due to a dirty air filter, then it's because your evaporator coils need cleaning, or your system is low on refrigerant, or your blower motor or capacitor is bad, or you have a collapsed return air duct.

Causes and solutions:

Bad Capacitor- Replace Capacitor
Bad Fan Motor- Replace Fan Motor
Bad Defrost Relay- (for heat pumps) Replace Defrost Relay
Burnt, broken, or loose wires- Replace Wires

Causes and solutions:

Shorted or broken wires- Replace Wires
Bad Capacitor- Replace Capacitor
Bad Contactor- Replace Contactor
Compressor Stuck- Add a hard start kit or bang on compressor with a rubber mallet.
Shorted or Grounded Compressor- Test motor windings and Replace Compressor
Open Overload Protector- Test for continuity, may be open due to a faulty fan motor or a lack of refrigerant. Run water over compressor for 15 minutes to cool compressor down, then check continuity again. If Compressor starts, check pressures for indications of low refrigerant or high head pressures. If compressor doesn't start, allow it to cool down for a few more hours and check continuity again. If compressor still doesn't start...replace compressor.

Causes and solutions:

Shorted or broken wires- Replace Wires
Bad Contactor- Replace Contactor
Bad Thermostat- Replace Thermostat
Shorted or broken wires- Replace Wires

Note: On split systems, where half of your unit is on the ground outside(condensing unit), and the other half is located in a closet, garage, or the attic(evaporator): These two units are on seperate circuits. Therefore you should also check the breaker switch to make sure it's not tripped and the fuses at the disconnect. This is to ensure that you have power to your condensing unit. If power is found at the condensing unit, then one of the above solutions should solve your problem.

Causes and solutions:

Loose Comprssor hold down bolts- Tighten bolts found at base of compressor
Leaking check valve- Replace valve
Refrigerant over charge- Remove refrigerant to proper levels
Broken internal springs- Replace Compressor