A/C not blowing cold air

Hi there,

My wife's van listed above quit blowing cold air when the A/C is on.

I have checked the following components:

Refrigerant pressure - OK - cycles between 25 and 50 psi on the low side.
Compressor Clutch - OK - cycles on and off.
Fuses and Relays - OK - No issues found.

I was told at an auto parts store the next thing to check is the AC Heater Blend Door Actuator.

Does anyone know where it is? Or perhaps what the next thing to check is?