Kharn

A few days ago, my '94 S-10 Blazer (manual AC/heat controls, converted to R134A in '03, low pressure switch replaced in '05) would blow air so cold that it would almost freeze your hands on the wheel. This week, even on max it is just blowing "cool", not warm, but not nearly as cold as it used to be. Max A/C and full power on the fan produces cooling approximate to minimum fan & normal A/C previously, I can feel the air has a bit of a chill to it not from the speed of the air.

Inside the engine compartment, everything isvery cold with condensation present. I hooked up the gauge from an R134A refill kit to the low pressure port, it showed pressure in the 45psi range. The clutch stays engaged, it does not cycle on/off.Suffice to say, I believe the AC system (evaporator/condensor) itself is working properly, but a little high on pressure, leaving the problem to be in the ductwork.

When switching from HTR to Vent there is a mechanical noise, like a small door opening. When switching between Off <> Max <> A/C <> Bi-level there are no noises similar to the HTR -> Vent noise. I remember previously hearing that noise when moving between Max AC and A/C, but it is not present now. Airflow changes locations properly between defrost, feet, bi-level& vents.

My best guess isa divertor door that allows air to bypass the heater core is stuck in the heat position, but I cant find it. I opened up the dash, took out the radio and the inspection port at the back of the glove box but that only gave me access to the temperature adjustment door which operates properly in relation to the temperature slider.

Any idea where to look? How far into the dash am I going to have to dig to fix this?