I'm new to this forum so hopefully I'm posting this in the right place, if not I apologize.

Anywho, I have had the wierdest hvac problems on my ram since shortly after I got it. (Purchased used with around 17000, has 83000 now). The selector dial on the hvac control (I think that's what it's called) that chooses between feet, defrost, vent, inside circulation, etc. has been off - meaning nothing seems to match up. For example, when I put it on vent (meaning the vents that blow at your face), it blows floor and vent, also on this setting its on inside recirc... which shouldn't be on until the last two ticks where it shows the inside recirc. Also, every month-ish, while driving the truck, and using either the heater or a/c, all of a sudden both the a/c light and defrost light will steady blink on and off, for about a 1/2 second each time, and it does this for around a minute. It does NOT look like a short at all - much too consistent, almost like the computer is trying to tell me something. While it does this it will switch to heat by itself (if its on a/c, or if its on heat it will switch to a/c) and I will loose all control over the hvac, turning the dials does nothing, and pushing the a/c button and mirror defrost button does nothing. Then it will switch back to whatever setting it was on before and act like nothing happened...

I guessed that it was the hvac controller, which I believe is right behind the *****. While searching this I came across the Heater Treater website, and learned quite a bit there - and figured that was my problem. So I pulled off my dash and looked at all the doors and motors. Unfortunately (I was hoping something would be broken so I could prevent myself from going crazy over this) nothing was broken, it seems that all the doors are intact, function properly, and seal well - though their operation does not correlate to the setting on the selector dial - they seem fine, so now I am back to thinking its the hvac controller.

The newest problem is with the heater, it blows nice and hot on the defrost and passenger side but blows cooler on the driver side feet.... I figured the blend door was the problem, but I checked that with the dash off and it is operating properly. This makes me think there may be a blockage in the heater core? Perhaps time for a flush (I haven't ever changed the antifreeze, prob should).

The moral of the story is the blend door, recirc door, and mode 1 and 2 doors seem to be in good working order as well as the motors that control them, though they do not operate according to what setting the dial is on. I have heard it is possible to read hvac codes, but I have no idea how... asked a local dodge dealer but they said they'd have to look at it...

Please, I hope somebody out there can help, I'm going mildly crazy over this.

Thanks!

 

most likely your blend doors are broken, I have a similliar issue, when I turn the A/C ON, it will blow ICE cold on the (2) drivers side vents but blow cool on the (2) pass. side. Also, when I turn the heat on and want the heat to blow on the floor, the (2) pass sides, will blow on the floor and blow a little on the face, im pretty sure its the blend doors, since my friend had blend door issues on his 2003 ram

 

That's what I was guessing, but I took the motor off of the blend doors and manually moved them and they seemed to seal fine, and nothing seemed to be broken, I watched the motor while changing the dial from cold to hot and it would stop at full cold and full hot (wouldn't keep spinning as if the door axle was broken). It seems as the doors and door motors are all doing their jobs, just not correctly, which makes me think its the hvac controller

 

Interesting - this is what I just found - sounds like this guy was having the exact same problems.

http://en.allexperts.com/q/Chrysler-...s-Flashing.htm

Would I need to go to the dealer for a fix? Or can I rent something through a local auto parts store to fix?

 

def. not the dealer, this is a HUGE PITA job, the whole dashboard has to come off.

 

You're saying the dash needs to come apart to read the codes for the hvac system?

 

No, the whole dash has to come off to replace those blend doors

 

Yes I am aware of that (crossing my fingers that isn't the problem!). All the doors seemed fine when I checked it out, all seem to seal fine and nothing seems broken on any of them, as well as the motors that drive them. That is why I'm thinking it must be a computer deal... And I guess the tool Dodge uses - DRBIII - is more expensive than my motorcycle was... so I may need to make a trip to a dealership unless an auto parts store has one

 

Well from what you described I would think all your blend and mode doors are fine. A few posts that I have read (hear and other forums) from the guys that tore everything apart usually said the doors wouldn't operate at all or just flapped around or the gear driven axles were stripped out. I'm with you thinking it's something with the HVAC controller.
I don't know if the DRBIII is the same as the StarScan tool, I'm sure the StarScan is pretty much a dealer only tool that is capable of changing and diagnosing the computer and truck electronics. The DRBIII might be available at some authorized repair shops, if so hopefully they can do the diagnostic and reset the HVAC controller.
HammerZ71 seems to know a lot regarding the StarScan tool. If he doesn't see this thread and chime in with his knowledge maybe you can send him a PM with a link so he can shed some better light on this for us all. If I remember I'll give my shop a call and ask them if they have a DRBIII tool

 

Thanks for the info, I do believe all the mechanics are ok (for now) and it's a computer issue. My guess was maybe the hvac controller (which I believe is the unit right behind the *****) maybe just went out... My question is if it needs to be recalibrated or whatever that dbr tool does, why would it have come out of calibration if all the motors and doors are ok? Not sure if it would be related but on another note I've had all gauges go dead while driving, for max 10 secs, then reset, and now the wipers seem to operate erratic at times, not according to the setting it's on, and I've had them randomly wipe without the wipers turned on... Maybe I should consult a priest for these issues? :P