2002 Dodge Ram 1500.... No heat coming from vents?

check t stat could be stuck open or you lost vacuum to heater door check to make sure its moving all the way over

I have a 2002 dodge ram 1500 and the heater works somewhat on low speed, but blows cold any higher. I have had the heater core replaced last year with the radiator and had it blushed a week ago. It works for a very short time and then works now and then. I was idling yesterday and it started blowing cold...I left it run, then it started warming up again??? Replaced the thermostat and the heater core was flushed, nothing bad came out of it. Antifreeze is new and looks real good, nothing in it at all. Help!

take a small rubber hammer and tap on the thermostat housing to loosen the thermostat but do not use a regular hammer because this will brake housing for thermostat - when you do this make sure that the truck is running with the blower in on position - you will hear the difference when it opens the thermostat because it will get slightly louder just keep putting your hand in front of the vent to check the difference in temps.

You might have lost vacuum to the reservoir that holds air. Heating and cooling vents are controlled by "gates" that blend air and move into the warm or cold regions and are moved by vacuum. Check a black tank under the good that looks like a coffee can.

Thermostat might be stuck open, or your heater core is finally clogged to the point of no return and you need to flush it out, or reverse flush it.

the resistor is blown if no air is coming out..or somnething is wrong with the vaccum lines

if not it might be the thermostat

there are 2 elctrically controlled mode and blend doors. the doors break at their driveshafts. there is a reivised door that will not break. the dash has to be removed to replace the small box sub section.

Low coolant level.

Got a leak somewhere?