Toyota Repair: 04 Toyota 4 runner A/C not cooling, 4 wd, toyota 4 runner

Question
Hi Ted .. I have a 04 Toyota 4 Runner SR5 6 cyl. 4 WD with about 40,000
miles ...The A/C has always operated fine and without any issues up until this
past few weeks it didn't seem to be as cool as it should and after inspecting I
noted that there were bubbles in the sight glass which led me to believe that
the system was low on freon, I added freon to the point that the bubbles
cleared and I noted the aluminum low pressure line from the firewall was
noticeably  colder and sweating however the outlet air  vents in the dash were
only, at best , producing cool air but far from adequate cold air, I also noted
that the heater hoses both supply and return from the firewall are quite hot
however I don't know if this is normal or if for some reason the heater is also
operating at the same time as the A/C ... I can't locate a in line valve for the
heater to verify if it is open or closed and at this point I am baffled!  Any help
or advise will be appreciated. Thank You, Quentin

Answer
The heater core has hor coolant going through it all the time, this is normal, the cold air/hot air is directed internally with air blend doors, it may be a problem with the controls on the dash, it uses a pushbutton array for the controls which controls the air blend doors and the air flow through servos, don't have a quick answer, if it's auto a/c it will have a self diagnostic system which can be accessed at the dealer using the diagnostic tool.