Heater blend door failure - I think...2004 V8

[gimmea250swb]

I posted this earlier, but labels it as the wrong year. 2004 V8 Limited

My son has the car and is coming back over Thanksgiving. I'd like to get inputs before the car gets here since he won't be home long. There's no heat in the cockpit despite the setting. He's in the mountains, so defrost is key to me.

This is what I remember from the last time I tried troubleshooting...

- input and output of the heat exchanger by your feet are hot suggesting it's not heater core blockage, right?
- the solenoid on the left and right side move when adjusted. I recall seeing the arms move.
- there's no hot air high, middle or low
- there's a minor "fart" of warm air when it goes to defrost, but it cools down to ambient quickly

So I think the diverter inside the box is broken somehow. Any thoughts on the next move? I plan to air blast behind the console to make sure there's not blockage around the core, but suspect that won't do anything. Other than that, not sure what to do. My biggest concern from a safety perspective is to get the defrost working. I'm happy to cut into the console to direct the air permanently to heat if that's what the problem is.

Thoughts?

 

[Jeebus]

I went through your posts to see what you've attempted, but no mention of the blower motor resistor. Some posts have had people with working AC but no heat, heat only but no AC, etc.. I haven't looked into the part number for your vehicle, but a quick search on Amazon shows a sub $50 part.

 

[SocalSam]

My guess is mode servo. Hopefully door is not broken.

 

[gimmea250swb]

Looks like I can get the resistor pretty cheap. It's worth a shot, but not sure that's the problem.

What is the failure mode of the blend door actuator? If I switch from hot to cold, would the actuator move the arm? I've got dual climate control. when I move hot to cold to hot, I can see both actuators moving the linkages. If the actuators are broken, would they do this or is there something else that breaks?

Both the input and output on the heat exchanger are hot...