This might be a silly question, but do you have a temperature control knob that says warmer? If I am picturing what you are saying that is the heater control valve which controls the flow of the water into the heater core. Is your truck bypassing that valve somehow?


A day without laughter is a day wasted- Charlie Chaplin
When wrestling a grizzly bear, you have to keep at it until the bear gets tired, not when you get tired.

1948 Chevy 2-Ton