Car Maintenance And Repairs

Dodge Ram Heater Control Problems- What To Do?

Mike Cross
Updated Aug 27, 2021
Dodge Ram heater control problems

Dodge Rams are a dependable truck with loyal fans. However, some drivers notice that there is often a problem with the heat controls. This can be an annoying problem when it is cold out or you need the defroster or a sign of a bigger problem.

Dodge Ram heater control problems
Dodge Ram heater control problems

If you notice you are having trouble with the heat controls in your truck, it is important that you figure out the reason why and take steps to fix the problem. Problems with your heat controls can have many reasons so you will need to figure out what the issue is and correct it. Your heat control problems may be due to a broken mixer box, a faulty switch, a vacuum issue or a problem with the blend door.

If you have checked the motor for your heating and AC and you are confident it is ok, you need to look at other possibilities.

What if I have a broken mixer box?

The mixer box is made out of plastic and you will need to remove your dashboard to reach it. It works with vacuum action, so you will need to be sure the vacuum hoses are working properly as well. To check the vacuum hoses, you will need to have your truck running. When you step on the gas, see where the air flow goes and then when you take your foot off the gas see what happens. Replace the vacuum hoses first. If you still have a problem, then replace the mixer box. Because the mixer box is located in a spot that is difficult to get too, you may want to have a professional check it and replace it for you.

Check heating system
Check heating system

Maybe my blend door is broken?

There are 4 blend door actuators under the hood that are connected to your A/C and heat switches.

The first one to check is the one over the gas pedal. Check this first since it is in a position that makes it easy to inadvertently kick it out of position. You need to remove the kneel panel, but you do not need to remove the HVAC housing.

Use a good light to check that all the connections are plugged in tightly and make sure the actuator door is not stuck or broken. You can do this by having an assistant move the switch that controls the A/C and heat vents in the truck.

Is my blower switch bad?

It is also possible that you are having heater problems because your truck has a faulty blower switch. You will need to check the wiring for any burns or melted areas. If you notice any at all, you will need to replace the wiring. If the wires are fine, then consider replacing the switch itself. It is easy enough to purchase a new switch through the dealership or your local parts store and install it.

Is it possible the motor is going bad?

You may also be having problems because the motor is going bad. You can check the state of your blower motor with a voltmeter.

If you notice little life left in your motor, you will need to replace it. Simply purchase a new one and swap it with the dead one. It is a good idea to replace any wiring too, so that you know all the parts are brand new.

Points To Remember

There are many different reasons why your Dodge Ram may have heater control problems. The issues could be because of damaged wiring, blend door issues, vacuum hoses losing suction or a broken mixer box.

Check the blend doors first. It is possible that one or more of them is stuck in a certain position. After you have checked them all, you should be fine if the problem was a stuck door. If not, you need to look further.

The next place to check is the vacuum hoses. If the vacuum seals are leaking, then your heating system will not be getting enough suction to maintain a properly working heating and cooling system However, replacing the hoses and seals should take care of the problem.

It is also a good idea to check all wiring and switches. Check to see that none of them are burned out or melted. If a wire is damaged be sure to replace it. If the blower switch needs to be replaced, then it is a good idea to replace the wires as well.

If after checking the vacuum hoses you continue to have a problem with your heater controls, it may be time to check the mixer box. To access the mixer box, you will need to get underneath the dashboard. This can be tricky and it is hard to access this area. At this point, you may want to have a professional complete this repair.

Your local dealership or auto parts store will be glad to help you find the correct parts that you need. You can also find this information in your owner’s manual. If you are not comfortable taking your dashboard apart, then take your Dodge Ram to the dealership for servicing.


The heat control on your Dodge Ram is a necessity during the colder months and when you are trying to defrost your windows. If you have heater control problems, they will need to be addressed. Recognizing that there are many reasons why you could be having issues, you can start to check one possible area at a time. Start with checking to make sure the blend doors are not stuck. After checking the doors, move on to checking wiring and switches. Check to make sure these are not burned or melted. If you have to, these are easy to replace with new ones.

If you are still having heater control problems, be sure to see your local dealership or mechanic. They will be able to help you check for mixer box issues and will have the tools to do it.

With a little bit of time and patience, you can figure out why you are having heater control problems and take steps to fix them yourself.

Mike Cross
Life is too short to drive with stock audio

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One comment on “Dodge Ram Heater Control Problems- What To Do?”

  1. I have a 2002 3500 Dodge Ram 4x4 . I turn my AC on and works for a few minutes then it starts blowing heat?

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