York YH9FYC18BAH-A-X Service Manual page 21

Check whether terminals
on indoor pcb is well?
Electrify the machine again and turn it on in the cooling operation,
Measure voltage between the positions 1and 3 of Terminal CN5 on
the indoor PCB
the voltage is about 90-220vac
check whether motor can run
when turn on the unit
the indoor motor is damaged and need replace
Pull out the terminals on the indoor
mainboard and reinsert them.
Yes
Measure whether there is voltage pulse(0-5VDC)
between the positions middle wire and black wire
of Terminal CN2 on the indoor PCB
the indoor pcb is damaged and need replace
19
Service diagnosis
Is it ok?
Domestic air conditioner