Air Conditioner Repair Troubleshooting

AC Repair Tips & Troubleshooting


Air Conditioner Repair Tips & Troubleshooting

With this brief guide providing by the experts at, you should be able to quickly identify & diagnose the most common air conditioner problems and determine the best course of action - whether it can be fixed yourself or if you should call a professional for further consultation. We do advise anyone who does not feel comfortable dealing with any electrical or mechanical systems to call a professional immediately to avoid both injury & damage to themselves and the system. 


Parts Needed

  • Voltage Tester (we recommend a non-contact tester for safety) 
  • Multimeter (for measuring voltage, current & resistance)
  • Screwdriver
  • Socket set


STEP 1: Furnace or Condensing Unit?

First, turn on your AC system so that it begins cooling your house to a lower temperature. Does the furnace start? If so, move on.


Outside of your house, you will have a box called a condensing unit - is the fan running? If so, it will probably sound something like a refrigerator - move on.


Either of these not running? Reset your furnace circuit breaker & try again - if either still don't start, call a professional.


STEP 2: Checking the Condensing Unit

TURN OFF POWER - disconnect & turn off the A/C & furnace breakers before you begin working with the outdoor condensing unit. 


USE VOLTAGE TESTER - to ensure wires going to condensing unit are not live. 


CLEAN CONDENSER COILS - if they are clogged, they can overheat & auto-shutoff



On the disconnect block, you can use your multimeter to test the Ohms going through each fuze.


If your fuze is blown, a quick fix would be to replace the fuze. 


This will not solve the problem however, as this is usually a sign of something failing consistently in the condenser unit. Call a professional.


STEP 4: Easy Fixes

If you have not identified the problem, double check that your furnace filter is clean, condenser coils are clean, registers in house are completely open. 


Any of these applied incorrectly can cause the entire system to overheat & not work properly.


The best thing to do after running an initial overview of these problems is to contact your local heating & air professional


We also recommend checking out a great resource by our friends over at the Family Handyman