Toyota Repair: AC smells after use, drain tube, excessive moisture

Question
2003 Toyota Tacoma Extended Cab 4WD AT 5VZ-FE 18,000 Miles

After I use the AC, the air coming out of the vents has a musty smell that takes about 10 minutes to go away.  I don't use the AC that often, and when I do typically I have the air supply on fresh, not recirc.

I checked the drain tube from the AC box and it appears to be OK, with some water coming out of it.

Is this normal because I don't use the AC that often?

Answer
The smell is normally caused by mold due to excessive moisture in the evaporator housing, this could be caused by a restricted drain tube, try using the a/c more and see if the problem clears up, with the fan on high try spraying some deodorizer into the intake air ducts just below the windshield on the cowl.