Trane 4TXM2318BF300AA Service Manual page 136

[9] DC Fan Motor Failure
Check if fan motor wires are
conductive(to CN11 of PCB)
Power off and rotate fan
motor by hand to check
voltage if black and red
is 280~350V and black
Y
Check if motor is
running
Y
if there is obviously
friction
N
Test the terminial
and whiter is 15V
Y
Replace fan motor
N
Replace wire and test again
N
Replace PCB
Y
Replace fan motor
N
Replace PCB
134