HVAC question.

[rscurtis]

I had an issue with my '03 the other day where the HVAC did not respond to the change of modes. At first, I thought it was time to do the mode and defrost doors (already did the recirc door), but later in the day, everything started working fine again. I was under the impression that once a door fails, it stays failed. Could this problem be in the control head itself?

 

[HOBrian]

It's funny you bring this up! My defrost/floor door does not work for a hill a beans in the winter, but the summer it works just fine. I know the door is broken. just my . 02

 

[Prairie Dog]

Rather than break, the splined part of the actuator at the end of the door can become worn and stripped out with age. When this happens the doors become intermittent in operation. There was a write-up in the TDR a while back about this.
There's also the possibility that the control panel is failing but this is a bit more rare.

 

[rashwor]

Interesting that your problem came up. I just replaced the A/C control module in my truck Saturday. My symptom was that everything would work fine at the beginning of the trip. Drive and get everything warmed up good and the stop and kill the truck for a errand. Come out from the errand a few minutes later and the A/C blower wouldn't blow once the truck was cranked again. The blower would not blow again until the truck had completely cooled down (1 - 2 hours). I found that the vents were not changing either when the blower was not working and the A/C compressor indicator light would not go off with the blower switch when the blower was not working either.



The local dealer had the in-dash control unit for $175, so I replaced it Saturday and the blower control and vents have worked as they should since, but it has been cool here since I installed the control and it only acted up in the middle of the day when it was hot outside... I think I fixed it and for that price, I hope so.



Here is the link for my thread: https://www.turbodieselregister.com...ions/237037-c-defrost-blower-not-blowing.html

 

[rscurtis]

I just looked at the electrical supplement to the service manual, and it shows two mode motors in addition to the blend motor. What are the chances that both mode doors failed at the same time? When I have a chance I'll pull the control and operate all the doors with the 9V battery adapter that I got from Heater Treater when I did the recirc door.

 

[Shadrach]

Here is a cure HeaterTreater™. Mine does the same thing. One of these days I'll fix it. Shad