Unlock the Right Part
for Your Repair
Find the exact part you need
Enter your model number to see parts that fit your machine.
Price Match Guarantee
In-stock parts ship the same day
365-Day Return Policy
Price Match GuaranteeChoose Product
Identify Problem
03
Find Solutions
HomeRepair HelpMedallion Central A/C RepairMedallion Central air conditioner wall thermostat not working properly Repair
Medallion Central air conditioner wall thermostat not working properly
If your Medallion central air conditioner thermostat is not working, the wall thermostat is the most likely cause, especially if the display is blank, the controls do not respond, or the thermostat is not turning on the AC. A failed wall thermostat can cause the same symptoms when its display is dead or it cannot communicate with the air conditioner. First, check and replace the wall thermostat batteries if equipped. If the problem continues, the Medallion central air conditioner control board may not be supplying the thermostat with 24-volt power. Less common causes include an incoming power problem at the furnace or air handler, a tripped circuit breaker, blown fuse, turned-off unit switch, or damaged thermostat wire. You can inspect batteries and visible wiring, but testing voltage, the control board, transformer, or circuit wiring requires caution. Turn off power before opening equipment, and have a qualified HVAC technician handle 240-volt line-voltage work. Enter your model number to find the exact replacement wall thermostat, wall thermostat, control board, or other part for your specific Medallion central air conditioner.
01 - Medallion Central Air Conditioner Wall Thermostat
The wall thermostat is responsible for controlling components and regulating the home's temperature. The thermostat can be powered with 24 volts from a control board on a separate unit like a furnace or air handler, or from batteries in the thermostat itself. The thermostat also has terminals to receive and distribute low voltage 24 volt power to run different HVAC products such as a furnace, air conditioner, or heat pump. If the wall thermostat is receiving power but the display is dead, or it will not send power out in the appropriate modes, the wall thermostat will need to be replaced.
Enter model number to search for the required part specific to your product
Highly Likely
02 - Medallion Central Air Conditioner Wifi Thermostat
The WiFi thermostat is responsible for controlling components and regulating the home's temperature. The thermostat is usually powered with 24 volts from a control board on a separate unit like a furnace or air handler. The thermostat also has terminals to receive and distribute low voltage 24 volt power to run different HVAC products such as a furnace, air conditioner, or heat pump. If the WiFi thermostat is receiving power but the display is dead, or it will not send power out in the appropriate modes, the WiFi thermostat will need to be replaced.
Highly Likely
03 - Wall Thermostat Batteries
Most wall thermostats are either powered by an enclosed battery or by the furnace or air handler control board. If the thermostat display is dead, you can remove the thermostat cover and look for replaceable batteries. Replace the batteries if needed and check operation.
Common
04 - Medallion Central Air Conditioner Control Board
The control board regulates the power supply to all of the components in the system. If the control board fails, it might not send voltage to the thermostat, leaving the thermostat inoperable.
Less Common
05 - Incoming Power Problem
Check to see if there is power to the furnace or air handler. One or more indicator lights on the control board should be illuminated. If there is no power to the furnace or air handler, check to see if a circuit breaker has tripped or a fuse has blown. Confirm the power switch on the side of the unit is turned on.
Less Common
06 - Bad Wall Thermostat Wiring
In order to send signals from and to the indoor and/or outdoor units, the wall thermostat uses a group of wires usually called thermostat wiring. If the thermostat wiring gets damaged, certain functions of the system or the thermostat itself may not function properly. The thermostat wiring can be checked for power or continuity with a multimeter. The wiring is usually industry standard colors: Red/White/Yellow/Green for a four-wire system.
Less Common
Frequently Asked Questions
Why is my Medallion thermostat not working or showing a blank display?
Why is my thermostat not turning on the AC?
How do I troubleshoot bad thermostat wiring on a central air conditioner?
Can a control board or incoming power problem cause a thermostat to stop working?
How do I identify and buy the correct Medallion central air conditioner thermostat or replacement part?
Shop by Medallion Central Air Conditioner Parts
Our Story
Family-owned and operated since 1912, Burke America Parts Group is the longest-running genuine appliance, HVAC, and outdoor power equipment parts solution in North America. At Repair Clinic, we're proud to be an international brand trusted by the pros as well as the DIY community.
About Repair Clinic
© 2026 RepairClinic.com