Why would a/c work in rear seat and not the front seat? on 2004 Honda Pilot

The a/c works fine in the back but the front is blowing hot air.

Asked by for the 2004 Honda Pilot
poss are endless, exp valve,actuator or several other issues
1 more answer
Automatic climate control -control unit is probably faulty. Will it switch to defrost and still blow warm air (onto the windshield)?