Heater in 2005 dodge caravan blows but the air is barely warm and not all the time.

This could be due to a fail temperature ( blend door) actuator for the driver side.

Need to remove fan and test it on a bench by connecting it directly to a car battery. Removing items like this buried in the dash takes a long time, and its tricky to put back together.

Yes . Your heater is actually not an Electrical Heater or a Separate Heating system . Actually if uses the same Radiator Line . When Radiator is heated up it is cooled down with radiator Fan and coolant . But when you use the heater function , this hot fluid is passed through a heating coil tube and blower fan is used to take that heat inside the car .
So I think now you understand , why you are not heated up in a short run . You really need to make the Engine + Radiator Warmer ( that is natuarlly happened when you run more) to get Warm air inside.
Please rate my answer fairly and Support me With Regards and Season's Greetings Deepak Richard

this sounds normal in very cold conditions! The air is never hot when you first start the car in any car, until the engine warms up, then the heater air will also warm. You could check your anti-freeze level for the first thing. If you don't have enough anti-freeze, it won't run through your heater to give you the proper heat

There is a recall that has something to do with the air/heat system in 2005 Dodge Grand caravans. Recall F01. Here is a link. I had mine done two weeks ago, cost me nothing. My air conditioner was overheating.

the most probabale cause of this would be a disfunctional hear core if you replace your heater your heater will more than likley work the the way it's supposed to

If you have the heater control up front on the floor or on defrost you should check that the heat is not blowing from under the d/p seats. If you move the heater control to dash you should have it coming out the top vents.

You could be having a coolant problem and need to check that first, If coolant level is normal you might have a thermostat going out. Both will cause your heat not to warm up at normal speed. If you need any thing let me know.

You have a circulation problem, heater core may have restriction that why heat only comes when you drive ,also you may have a thermostat that stuck in the open position. Good Luck

there could be an air lock in the system, pluged heator core, a bad thermostate or control modual. try bleeding the air out through the bleeder screew if there is no heat after that have the control modual tested if its okay try having the cooling system flushed then if it still doesnt heat intall new termostate

check the coolant level, I had the same problem low coolant level.....no hot water to the the heater coil.