The heater is not working in my 79 pickup. It has a new heater core, water pump, t.stat. It blows normal, but the air is warm not hot. I pulled the dash apart and the doors that let the air in are working normal. Both heater hoses are hot, so its getting circulation. The truck runs at proper operating temps, around 195ish. It has a regular flex fan, and there is cardboard in the girlle. Any ideas?

 

Did you or can you touch the new heater core and see if its hot like the hoses?