I have no heat. Its a 99 blazer. The heater core is not leaking. I took off both hoses and blew out the heater core. It was pretty dirty. I got the blazer up to operating tempurture and there it only one hose thats warm/hot and that hose goes to the water pump. what else can i check?

 

Correction*** The hose that's warm is the hose coming from the thermostat housing not the water pump... So if the hose going from the thermostat housing to the heat core is warm/hot and the hose going from the heater core to the water pump is cold, That means I have a clogged heater core?

 

Sounds like it.

 

I concur. Definitely sounds like a heater core restriction/plug.