I have a dodge ram 2001 5.9 the heater does not work, replaced the thermostat. is there a fuse for the heater some where? the a/c does work.

Check and make sure you did not pull lose the duct work that directs the air flow to your feet. Common mistake most people make when replacing the heater core. That would be the first thing to check . Good luck.

Check if your rubber hoses that lead to the heater core have an inline valve. If the do, it sounds like it is not opening to allow circulation. normally they are vacuum operated

Replace the relay under the hood .There is a black box that wii say relays check your relals ther sould b 2 also check fuses Good Luck

I see your post was a while ago. I hope this helps you or anyone ells having Dodge over heating issues.

I have a 2002 Dodge Ram 1500 and a 2005 Dodge Grand Caravan. I also owned a 2001 Dodge Grand Caravan. ALL of them had thermostat issues. When you replace the thermostat make certain you get the proper heat rating. If it is rated tool low, then the check engine light will trigger the code that the engine is not heating up fast enough. I also recommend going with a 'fail-safe' thermostat. These thermostats fail OPEN rather than closed. My 2002 RAM factory thermostat failed closed, built up pressure, then blew half the water out from under the radiator cap. This happened in less than 35k miles. The dealer replaced it. After a couple of years it failed again. Make sure you have 50/50 mix of anti freeze to water. This raises the boiling point of the water, makes it more efficient for cooling the engine, treats the water so it does not corrode and scale up the cooling system and helps keep the liquid from boiling off there by reducing the volume of fluid in the cooling system. Also, BOTH my 02 RAM and 05 caravan developed a leak in their radiators. They were slow leaks and I did not notice it until I did some standard checks and found the coolant was low, Most shops can run a pressure test for less than $40 to let you know if your radiator is leaking.

You should also make sure that your AC cooling fans is running. There are fuses and solenoids in the fuse box that can sometimes go out. When you AC is on this fans will turn on. If not, it could create a lot of extra heat.

Shawn

check thermostat if that is good then replace heater core

do you have coolant in the truck? if so the next thing to check would be the thermostat. if that goes bad or sticks it wouldn't let any water pass thru to the motor.does your a/c work if so in might be the heater coil gone bad if it's not the thermostat.

Do the taillights work? If so it might just be the bulb. If not then the wiring is broke some where or loose.

Hey,
I'll assume for now that the blower motor is working.
Now, there are a couple of things things to check.
1. Easiest thing to check is the coolant level. If the coolant is low, your heater will not give any warm air. Hopefully this is the problem as it's the easiest fix.
2. The thermostat. When the engine and coolant are hot, your top rad hose should be hot as well. See if the rad hose is hot to the touch. If it isn't, your thermostat might be faulty. It's a fairly easy and cheap fix as well.
Good luck.

are heater inlet outlet mix valves standard for all dodge heater cores. I have 2001 dodge cummings blows warm air not hot when gauge is 195 degrees would there be a mix valve under the dash because it is not inline outside the wall

If the air deflector is moving correctly, Make sure your thermostat is not hanging open and that your coolant level is up to standards. While the engine is at running temp. check the two hoses that go through the firewall to the heater core. If they are both hot than one of the servos, vacuum or motorized may not be moving the deflector doors correctly. Try to hear any movement when you switch back and forth between defrost and floor heat.I doubt you need to replace the heater because of the age of your vehicle. Try to watch for any movement under the dash while you move the control. Good luck, Dana