Test the ECM motor with the UltraCheck-EZ diagnostic tool

What is going on

The UltraCheck-EZ (part UTT-01) is the preferred tool to diagnose the ECM motor. Use the LED and button status to decide the next step.

Check in this order

1. Disconnect power to the furnace.
2. Disconnect the 4-circuit control harness from the motor.
3. Plug the 4-circuit connector from the tool into the motor control connector.
4. Connect one alligator clip to a ground source and the other to a 24VAC source. The clips are not polarized.
5. Only connect the tool to 24VAC. Other sources can blow the non-replaceable fuse and damage the tool.
6. Turn on furnace power.
7. Press the orange power button to send a run signal. Allow up to 5 seconds for the motor to start.
8. If the orange button does not light, check for an open fuse or a bad 24VAC connection.
9. Use the indication table to decide the next step.
10. Press the orange button to turn the motor off, disconnect power, remove the tool, and reconnect the 4-wire harness.

More furnace guides

• Airflow lower than demanded, furnace runs on low stage when high stage is expected
• Alternate combustion air opening (upflow or horizontal)
• Alternate vent/flue location (upflow or horizontal left)
• Annual inspection checklist
• Auxiliary limit control (location and purpose)
• Auxiliary limit switch open (blower compartment)