my heater is not working correctly, when you turn on the heat it blows warm air for less than 1 min then cools off, I have changed the thermostat. Any thoughts, Thanks (2003 Ram)

 

Heater coor ?

 

Check out the cabin air filter and theheater core. If you are getting cool air after a little warm air - then you basically have no air flow through the heater core, and cabin air is simply being recirculated by the core, no outside air is coming through it. If thevanes on the heater core are clogged, you have pretty much the same situation - I had this problem. Once everything was cleaned up, and the cabin air filter was replaced, my problem was solved. Since you are getting some warm air, I would guess that the heater core itself isn't clogged (coolant is flowing freely through it). Good Luck!

 

You could also try to check the coolant levels. Proper coolant levels helps the heater to run warmer. And check if its clean. If not, replace then check the temperature afterwards.

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