I had a problem with the temperature in the cab being too hot or too cold. This occurred while running the A/C or the heater. One click on the temperature dial was moving the blend door too much. The blend door actuator is located under the dash just right of center.
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So, I had to determine if the problem was with the temperature dial or the actuator. I depressed the little tab on the electrical connector and pulled it off the actuator. I stuck paper clips in the connector so I could check the voltage. Wrap tape around the paper clips so they don't touch each other. There are 3 wires. The center wire and the outside wire closest to the center of the connector are the ones I used. I started with the dial full cold and as I turned it one click at a time I recorded the voltages.
11.95 full cold
11.95
11.69
11.13
10.60
10.08
9.55
9.05
8.53
8.00
7.47
6.97
6.46
5.98 midpoint
5.48
4.95
4.45
3.95
3.42
2.94
2.43
1.93
1.42
.92
.42
0
0 full hot

Since there was an average of about .5 volts change for each click and no big jumps in voltage I deduced that the dial was good and the actuator was bad.
There are 2 screws and one post holding the actuator under the dash. The screw on the backside is very difficult to remove and requires either a flexible screwdriver or a 90deg screwdriver. There is a plastic coupling between the actuator and the blend door. It will probably drop out when you remove the actuator. Check it for cracks and replace it if there are any. After removing the actuator I of course had to take it apart.

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Of course there was no visible problem with it. I don't know why it wasn't working properly. So, I bought a new one and now have full control of the cab temperture. Not too hot and not too cold - just right.

 

pretty cool!!! (or hot, depending on your temp setting )

So you were able to remove the blend door actuator without removing the HVAC assembly?

How much was the part?

 

The actuator was only $130.

 

good info. thanks. i think there's something wrong with mine. the best i can get is luke warm heat but its too cold to work on it now. one of these days....

 

Great Post! Helped me a ton.

Where did you get your actuator? I can't find them even online, perhaps I'm looking under the wrong name? (Blend Door Actuator)

 

I have an 03 Dodge Ram 1500. The heat & air stopped working right at the same time 2 years ago. I can no longer tolerate freezing to death. Have had some people look at it with no idea of what's wrong with it. I cannot afford a dealer as to why it's still not working. Ok so, the blower motor works. The air flow changes from face, defrost, & feet when I change it. In the summer the ac blows hot. In the winter the heat blows ice cold. They both worked great before they stopped working. Please help

 

You really need to post this in the third gen ram section. Start a new thread please.

 

I did after I figured it out

 

Good enough.