Diagnosing Weird A/C Issue -- Mode Door? Blend Door?

[BigRedTahoe]

Hey guys,

I've got a 2001 Tahoe LS with A/C that hasn't worked since I bought it back in November. As it warms up, I'm trying again to diagnose it and coming up empty. Confirmed that it has refrigerant, and when I turn on the A/C the compressor lines themselves get ice cold. However that cold air doesn't make it to the interior.

My first guess was the blend door, but from what I understand if your blend door is busted the temp control won't work. Mine works fine -- turn it to hot and it gets hot, cool is cool, it's just not A/C cold. I know I need to fix the mode door, since the air only comes out of the dash vents, but since that's a pain I was going to ignore it. Unless that's my A/C problem, in which case I'll fix it.

Any ideas on what else it could be? Or how to check which door/actuator I need to replace?

 

[swathdiver]

Can you confirm that the blower motor is working?

Then can you confirm any movement of air from the dash to the vents to the floor at all?

How about passenger and driver side temperature control?

A Tech-2 is really needed to see if this is an actuator problem or a controller problem but you can still narrow it down by doing the above.