How to Troubleshoot a Window AC Compressor

How to Troubleshoot a Window AC Compressor
Written By
Tom Fritchman
Tom Fritchman
Published: Feb 16, 2011
Updated: Nov 20, 2021
2 minute read

If your window air conditioner ceases to cool your air, chances are its compressor is malfunctioning.

  1. Verify your power outlet works by unplugging the air conditioner and replacing it with a lamp. If the lamp turns on, then the problem is inside your air conditioner.

  2. Remove the terminal cover by unscrewing the four mounting screws with your screwdriver. These four screws are located near the four corners of your air conditioner’s front.

  3. Inspect your air conditioner’s compressor. If you see any cracked valves inside the air conditioner, then the entire compressor will need to be replaced. If the valves appear undamaged, then the problem is not the compressor. Instead, the problem lies in your air conditioner's electrical terminals.

  4. Locate the terminals labeled "C," "R" and "S." Inspect the wires connecting each terminal to the other two. If any of the wires appear damaged, they will need to be removed and replaced with your spare wire.

  5. Check the resistance between terminal "C" and terminal "R" by removing the wire that connects those two terminals and replacing it with the ends of your multimeter. If the multimeter reading shows a result higher than 30 ohms, one of the panels is faulty.

  6. Determine which terminal is faulty by repeating the resistance test for the connection between panel "C" and panel "S." Repeat the test again for the connection from terminal "R" to terminal "S." Use the process of elimination to determine which terminal will need to be replaced. If each of these tests shows resistance higher than 30 ohms, then the entire air conditioner will have to be replaced.

Things You Will Need

  • Multimeter
  • Screwdriver
  • Spare wires

Photo Credits

Jupiterimages/Photos.com/Getty Images

Jupiterimages/Photos.com/Getty Images

Tom Fritchman

Tom Fritchman is a freelancer who has been writing professionally since 2009. His first writing credit was actually a stage play called "Window Watching" performed at the Northmont Auditorium in Clayton, Ohio. He holds a Bachelor of Arts…

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