Turn on MAX AC but Dampers dont open

[Harmon]

AC is blowing cold, but not cold enough.  Guages show I have enough freon in the system.

Its my understanding when you have it on MAX AC, you are recirculating the cool air in your vehicle.  Well my dampers do not open to suck up the cool air in the cab of the truck. 

Anyone dealt with this?

[Lt.Del]

what do you have?  some trucks have vacuum controlled controls, some cable.

[Harmon]

Its a 1986 Silverado

[TexasRed]

SgtDel, is that what this here ball of doom is for:

http://www.autozone.com/autozone/parts/Motormite-Vacuum-Reservoir/1984-GMC-C1500-1-2ton-P-U-2WD/_/N-ik8mzZ93xvr?counter=0&filterByKeyWord=vacuum&fromString=search&itemIdentifier=439277_122285_13423_5520

[shane o]

I would also like to know the answer to this question, mine blows air but most of it comes out of the floor vent.

[VileZambonie]

If the vacuum reservoir isn't hooked up it won't change modes. Check that first.