If the air conditioning in your '95-'02 Dodge Ram has been charged up and still isn't working, there's a chance that the A/C evaporator has a leak and it's time to replace it. It might be that the heater core was leaking and caused the outside of the evaporator to corrode.
Replacing it is a big job, but a do-it-yourselfer with the time, tools and a factory service manual should be able to do it. Set a day aside and save a lot of money compared to having a shop do it for you. You'll find a number of videos on YouTube demonstrating how to replace the heater core if you want to have a look before attempting this job.
If you're replacing the dash in your truck, it's a good idea to go ahead and replace the heater core while you're in there. You won't want to do this job twice.