Trane
Fan Control Output Failure or Misconfiguration
Thermostat fan setting ON does not run the blower continuously
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Open G wire between thermostat and indoor unit, Failed thermostat fan relay, Indoor control board not configured for continuous fan, Miswired G terminal
How to Fix / Troubleshooting
Safety: Turn off power to the indoor unit before working on wiring.
- Step 1 – Verify fan mode: Set the thermostat fan to ON and confirm that the display indicates continuous fan.
- Step 2 – Check G output at thermostat: With a multimeter and fan ON, measure between G and C at the thermostat. You should see ~24 VAC.
- Step 3 – Check G at indoor board: Measure between G and C at the indoor control board. If no voltage, inspect the thermostat cable and connections.
- Step 4 – Confirm board configuration: Some Trane air handlers have settings for fan operation. Verify that continuous fan is allowed.
- Step 5 – If G signal is present but fan does not run: The indoor blower relay or motor control may be faulty and require professional service.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
Trane Smart Thermostat or Trane Indoor Unit Control Board
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements