Dodge: Dodge Ram No Heat, dodge ram, heat fan

Question
I have a 1999 Dodge Ram 318 2X4, 90K.  Same as the other guy, no heat. Fan motor does work. Here is the story.  In Dec. 04 I purchased a after market water pump & replaced it myself because the old one was leaking. A week later I took it to a service station to flush the radiator, I didn't want the mess ($60.) In January I was noticing no heat. I purchased a after market Thermastat ($4). But never had time to install it.  Took it to the same station and they flushed the heater core an replaced the thermastat($180). Still no heat (but it was a little better.  Mechanic said the thermastat was bad.  I put one in myself. Still no heat. Mechanic said it was a cheap Themastat so I bought one from Dodge ($25.00!) still no heat.  Took it back to the station and they said the engine was not heating up and it must be the water pump.  I hate to change it yet. What do you think?  

Answer
It is either the water pump or the radiator.Does the radiator have any build up in it?If they flushed the system it shouldn't have but they also shouldn't have charged you $180.00 for a fluid flush and thermostat either.It could be air in the system(radiator).After market parts are just as good as the original parts they just don't cost as much,don't let these garages tell you that the items you buy are just cheap ones,that's how these crooks make their money.Have you tried putting something in front of the radiator to cut off the air to it to see if that works,a piece of card board or something to completely cover the radiator while it's running,if it gets hot then it's not the water pump.