Calling all you HVAC experts

[Mark.Smith]

I only have air coming from the dash vents no matter where the controls are set. Everything else works, temp and fan speed controls are OK. Soooo, I bought the parts to do the defrost door fix. After a very nerve racking day of ripping the dash out and the HVAC unit, it turns out there's nothing broken, not one door#@$%! So now what? I don't want to put it back together until I figure it out. Anybody have any ideas? Are all the actuation motors the same?

 

[p-Bar]

Mine is doing the same thing I contacted heatertreater and here is what they said:
also they have video on how to do it
The problem on a RAM is the mode 1 door not switching away from dash vents and
diverting air down to the mode 2 door that chooses between floor and defrost
once the mode 1 door has switched away from the vent. The video posted in the
listing shows the mode 1 door repair and this is common on the RAM. The re-circ
door is usually the first to fail so I'd suggest finding the grate behind the
glove box opening and you can see/feel the operation of that door.

Chris A.
512-507-8467

Thanks for your interest,

Chris Allen
PO Box 151029
Austin, Texas
78715 1029

Heater Treater: Blend Door Fix, Heat and A/C Replacement Parts <http://www.heatertreater.net>

 

[Mark.Smith]

I have the parts to fix the rec door and the defrost doors but they don't appear to be broken. All the doors appear to move freely and none of the stops are broken. Would a bad actuator motor on the defrost door cause it?

 

[Bill Stockard]

I have the parts to fix the rec door and the defrost doors but they don't appear to be broken. All the doors appear to move freely and none of the stops are broken. Would a bad actuator motor on the defrost door cause it?

IIRC, if the doors are functioning properly, but not in the correct position, they need recalibrating by the dealer.



Bill

 

[GOlsen]

I'm not real sure how it works on your 05, but on my 98 everything is vacuum controlled. I had the same problem when the vacuum line going to the actuator broke.

 

[Bill Stockard]

I'm not real sure how it works on your 05, but on my 98 everything is vacuum controlled. I had the same problem when the vacuum line going to the actuator broke.

FYI, third gen HVAC doors are electric. DC servo motors. No vacuum on the truck exoept for Cruise Control on early model third gens and that is furnished by a small electric vacuum pump.



Bill

 

[Alan Reagan]

When I had an 05, I seem to remember that you could see the motor arm that connects to the door. I could move the control and see the control arm move. If it is not moving, then it's the motor.

 

[GOlsen]

FYI, third gen HVAC doors are electric. DC servo motors. No vacuum on the truck exoept for Cruise Control on early model third gens and that is furnished by a small electric vacuum pump.

Bill

Good to know, thanks.

 

[Wingate]

Plug the motors in and turn the keyswitch on, you should see the actuators perform their "sweep test"

Also, make sure the splines inside the door are not stripped.

 

[BIGNASTY]

IIRC, if the doors are functioning properly, but not in the correct position, they need recalibrating by the dealer.



Bill

Are you for real BILL? is this another way to get our trucks into the dealership? If it's not a crime it should be

 

[Mark.Smith]

IIRC, if the doors are functioning properly, but not in the correct position, they need recalibrating by the dealer.



Bill

It looks like this is what needs to happen as I reassembled everything and still no joy. What is involved, do they just plug the truck in and reset the computer?

 

[Bill Stockard]

It looks like this is what needs to happen as I reassembled everything and still no joy. What is involved, do they just plug the truck in and reset the computer?

Yes, I think so. I've never had it done (knock on wood) so I don't know what the tech actually does to recalibrate it. I'll check my Factory Service Manual tomorrow and see if I find anything.



Bill

 

[Mark.Smith]

Yes, I think so. I've never had it done (knock on wood) so I don't know what the tech actually does to recalibrate it. I'll check my Factory Service Manual tomorrow and see if I find anything.



Bill

Thanks much Bill!!

 

[Bill Stockard]

Mark,



I didn't find anything that described the procedure for recalibrating the blend doors. When a blend door actuator is replaced, it instructs to "Perform the heater-A/C control calibration procedure. It refers to "Heating & Air Conditioning/Controls-Front A/C-Heater Control-Standard Procedure-Heater-A/C Control Calibration". (I added the underline for emphasis. I could not find this section in my FSM. )



Evidently, there is a calibration that can be done. How it's done, I don't know.



Bill

 

[Wingate]

doesnt the HEATERTREATER website talk about the calibration of the motors. . I was under the impression the motors self calibrated at every keyswitch on cycle???

 

[Mark.Smith]

Mark,



I didn't find anything that described the procedure for recalibrating the blend doors. When a blend door actuator is replaced, it instructs to "Perform the heater-A/C control calibration procedure. It refers to "Heating & Air Conditioning/Controls-Front A/C-Heater Control-Standard Procedure-Heater-A/C Control Calibration". (I added the underline for emphasis. I could not find this section in my FSM. )



Evidently, there is a calibration that can be done. How it's done, I don't know.



Bill

Thanks again Bill!

 

[Mark.Smith]

doesnt the HEATERTREATER website talk about the calibration of the motors. . I was under the impression the motors self calibrated at every keyswitch on cycle???

I also found a site where one of the HEATERTREATER techs talked about disconnecting the batteries to "reboot" the computer. I tried this and it didn't work, although I thought I'd lose my radio presets and I didn't. Maybe I should have disconnected both positive terminals along with the negitives. I'll have a talk with the dealer service department and see what they have to say. I'm in Colorado Springs and I need defrosters:{

 

[Bill Stockard]

I'll have a talk with the dealer service department and see what they have to say. :{

I'm on pretty good terms with the guys in the service department at my local dealership. If I ask the service writer a technical question about a pending repair on my truck, which he usually can't answer, we walk in the shop and talk to the tech who works on similar problems. You might try the same.



Bill

 

[mwilson]

If any of you have a subscription to ALLDATA for your shops would you check for the recalibration procedure??



I say this because I have used ALLDATA DIY in the past and they will show procedures that can't be found in the FSM.



My '96 and '98 Town and Countrys would have issues with the heater doors freaking out and you could only get defrost.

ALLDATA showed the recalibration procedure and it amounted to holding two buttons down until all the lights on the panel flashed, then pushing another button to make all the doors do a complete sweep, that would sync all the stepper motors to the heater control panel.

Problem solved.



Maybe the third gens are not capable of that and must be done with the dealers scan tool, but I bet that there is a way around that.



Just thought that I would toss that out there.

You know me... ... .....



Mike.

 

[Bill Stockard]

If any of you have a subscription to ALLDATA for your shops would you check for the recalibration procedure??



I say this because I have used ALLDATA DIY in the past and they will show procedures that can't be found in the FSM.



My '96 and '98 Town and Countrys would have issues with the heater doors freaking out and you could only get defrost.

ALLDATA showed the recalibration procedure and it amounted to holding two buttons down until all the lights on the panel flashed, then pushing another button to make all the doors do a complete sweep, that would sync all the stepper motors to the heater control panel.

Problem solved.



Maybe the third gens are not capable of that and must be done with the dealers scan tool, but I bet that there is a way around that.



Just thought that I would toss that out there.

You know me... ... .....



Mike.

I checked ALLDATA-DIY for my '03 truck. It is about the same as the Factory Service Manual. No description of the calibration of the blend doors procedure or shortcuts from using a DRBIII scan tool. Maybe ALLDATA is different...



Bill