Carrier 42NQV009E Service Manual page 58

(2) Power is not turned on though Indoor P.C. board is replaced
<Confirmation procedure>
Turn on power supply.
Does operation lamp flash?
YES
NO
Is wired correctly to white and black
lead wires of terminal board?
– 57 –
NO
YES
FILE NO. SVM-07018
Correct wiring.
To item of
"Power is not turned on".