1990 Acura Legend LS- Interior glass fogs up. To clear, air conditioner needs to be turned on full blast. I have had the heater core replaced and the radiator is full. Also, The air conditioning does not keep up in the hot weather. It seems to come out of all the vents and you cannot target to the dash vents or the defrost vents or under dash vents. Solution?
The problems sound like the heater and A/C climate control cables were not put back correctly. The heater valve is near the firewall and has a cable running from the cold/hot adjuster. If it is not completely closed, it will keep A/C from getting cold. Look near firewall on passenger side of engine bay. You will see the valve with a hose from the firewall, to the valve then it goes to the motor. Set the cool/heat adjuster to cold and pull the cable out of the snap clip on valve whcih holds the outer sheath of the cable. Move the cool/heat control and make sure the cable sheath, outer case of cable, does not move. If it moves, you can try bending it so it will hold the cable.
The same thing is going on with the control for the climate door. It sounds like it is disonnected and need to be attached and adjusted in the same way. Look under the dash for a cable running from the climate controls to the heater box under the dash in the middle of the dash. It is harder to get to. Watch whcih way extends the cable out, while it is in that position, put the cable in the holder clip on the side of the heater box.