How do I put refridgerant in my truck? I have no A/C.

take it to a shop with the correct equipment to do it right.

I agree that a professional is the best bet. They vacuum out the system, check for leaks and install the correct amount of new Freon.

do you mean the hardware for making the air conditioned is there but not charged and with a bad filter/dryer~?

see above "needs freon" I dont think he wants to put freon in the motor hoping he will have a/c then. I would think it would be safe to assume he wants to fill the air conditioning system that currently exists with freon. A denali is top of the line no matter what the year it probably came with a/c.

there are ways to do it your self, but you'll need a vacuum pump and it will be far easier for you to just take it to the shop, because it's really not gonna ve much fun and besides they can do it quicker.