MAIN BOARD WJ26X20543

Hi Steve, If your air conditioner does not turn on and you have verified that the unit is getting power, you may have a defective control board part WJ26X20543. Most modern window air conditioners use an Electronic Control Board, or commonly referred to as a PCB, to control the individual components of the unit. If the fan or compressor circuits do not turn on, then the control board may be defective. Check the user manual for proper operation and verify that you are getting power to the unit before condemning the control board. Some control boards may have an internal fuse on them, so check for a blown fuse and replace with the same type and rating if necessary. Thank you for your question and good luck with your repair!