94 Plymouth Acclaim Heater Problem?

I have a 94 Plymouth Acclaim, 3.0 L, V6 and I have no heat. The A/C works, and air blows so it's not the fuse. I'm looking for where the heater switch is located under the hood. I've located the heater hoses and a cable that goes into the firewall immediately below the heater hose and the other end goes into a little cylinder that looks like a plastic container that 35 mm film comes in with a little periscope angled on top that hooks into something that splits into two other hoses. I can't find my Chilton's and the library didn't have one. I'm trying to figure out what's wrong with it and where the I can find the heater switch/valve.