A/C mode door calibration?

[stevenknapp]

I had the dash trim and AC controls off to check the antenna connecion on the radio. After reinstalling the A/C didn't work. I searched the service manual and it indicated that the mode/direction motors need to be calibrated after the controls are reinstalled. It refrenced the procedure, but I could not find it anywhere.



The A/C has since started working, but does anyone have an idea how to perform this calibration?

 

[thejeepdude]

Are you serious? Has everyone that installed an aftermarket stereo had this problem? Really interested to hear about this calibration process... . someone must know...

 

[Prairie Dog]

I've had that trim off several times and I can tell you there's no adjustment needed afterwords - it's all electronic. Maybe something didn't get plugged back in completely? Try taking it back off and reseating everything.

 

[stevenknapp]

It's all snug. It is all electronic and hence that's why the service manual DOES indicate that it needs to learn the door limits.



The A/C operation was erratic, then it just started working again. The mode and temp controls were also strange for a short time, then they started working normally too. Maybe it just re-calibrated themselves.



I did turn the key on with the A/C stuff unplugged. Maybe that's a big no-no.

 

[SRadke]

The door in the AC system on mine quit working to. It would always blow out the defrost vents and never on the floor. I took it to the dealer and they had to tear the whole dash apart to fix it.



-Scott

 

[stevenknapp]

Hmm... but mine started working again after a short time... . I suppose if it never happens again I don't need to worry.



I found instructions for older caravans to do this procedure without the diag tool. But nothing for the RAM.

 

[KHogan]

Anybody figure out how to adjust the door limits? My truck blows warm air when the thing is set all the way to "cold". Any suggestions? I'd hate like hell to take it to the dealer just for that.

 

[JHardwick]

Good luck guys! When you figure it all out let me know so I can train the local service department!



I've only had my truck in a couple of times and always had good results with my dealers service department ... ... ... ... until now!



In Feb the heater door quit working and would get stuck on either the floor or defrost.



I took it in and had the bottom of the heater box replaced with 400 miles of warranty left.



Last month the thing would just simply quit blowing air from anywhere while the blower was screaming!



Well, after I picked it up last Fri, it all worked fine ... ... ... ... until this morning!



This morning, I noticed a big difference in temp and volume of air coming from the passenger panel vents. Shortly after it lacked air volume from all vents. It still goes from defrost/panel/floor and back again, but lacks volume and makes the blower sound like it's ready to take off!





So, it's back to the dealer for the third time regarding the same problem and with 48,000 miles now. Good thing it was first "fixed" with 35,000 miles, lol.

 

[GDouglas]

If your blower is running hard but can't find any air coming out of any vents then your evaporator may be iced up if you are running the A/C. Mine has done this only once so far and it was 100% humidity outside with the sun shining just after a hard rain. I cut the compressor off for a few minutes and just let the fan run and once the ice started melting, my airflow reappeared.



I had a friend of mines 03 3500 do the same thing and he took it in to the dealer and all they did was to bump up the freon charge some. So far, he has not had a problem since.

 

[JHardwick]

Originally posted by GDouglas

I had a friend of mines 03 3500 do the same thing and he took it in to the dealer and all they did was to bump up the freon charge some. So far, he has not had a problem since.

The way I understand it, if you increase the freon you have less cooling capacity?

 

[Carlsummers]

Originally posted by GDouglas

If your blower is running hard but can't find any air coming out of any vents then your evaporator may be iced up if you are running the A/C. Mine has done this only once so far and it was 100% humidity outside with the sun shining just after a hard rain. I cut the compressor off for a few minutes and just let the fan run and once the ice started melting, my airflow reappeared.



I had a friend of mines 03 3500 do the same thing and he took it in to the dealer and all they did was to bump up the freon charge some. So far, he has not had a problem since.

I talked with the svc mgr at the dealership I use, and he told me that the '03 has a known problem with icing and reduced air flow/temp. Mine has done this 4 times. I was told that they have to replace a sensor which requires removing the dash. Taking it in Friday.....

 

[GDouglas]

It is good to hear that your dealer has a good idea of what may be causing the icing up. I think a few others on the board here have experienced the same problem intermittently.



Running a slight overcharge of freon will raise the operating pressures some, with the effect of the low side(evaporator) not running quite as cool as before. Please keep us posted for a fix! I have not come across any TSBs yet for this problem yet.

 

[SMillner]

I'm in the middle of the same problem. For quite awhile it did the fan blowing, nothing coming out vents or very little. Now I'm finally getting consistent blowing but i have cold air on the driver's side and not near as cold air on the right 3 vents, not nice when it is 100 deg here. The service manual repeatedly mentions the procedure and where to find it in the manual, but they apparently left the page with the actual procedure out Please let me know if you found anything out, I'm about to pay justanswers.com to get an answer before my helper in the passenger dies of heat stroke... ...

 

[JCleminshaw]

My A/C has just quit working. The dash light comes on, and the fan blows, but it does not appear to have the compressor running- any ideas? (Fuse looks good)

2003 SRW

 

[Belgrath04]

A/C Heater Control Calibration

For those of you who mentioned the HVAC Calibration

The A/C Heater Control calibrates each actuator individually.

Automatic calibration occurs upon power up after installing a new A/C Heater Control.

Manual calibration occurs by sending a command with the scan tool.



The purpose of actuator calibration is to determine the total span of door travel between physical stops.

To calibrate the actuator, the A/C Heater Control first moves the door to an end stop, and then counts the number of pulses it takes to move the door to its other stop.

An expected range of span is stored in the control's memory.

If the measured calibration value exceeds the expected range for this actuator, this DTC will set.

Note that the control clears all stored calibration faults at the beginning of the calibration procedure.

 

[JFought]

yea 65K and i think it has broken for the 4th fing time!!!!! right now in ft worth it been 100 and will be for about another week!!! great like always!!!!!

 

[mtnram]

Belgrath, I've got a question for you: Does only a new a/c heater control trigger a recalibration (I realize the scanner can trigger one).

If the batteries are disconnected and the control is unplugged from the harness, then reconnected will it maintain the "old" programming, or will it run through again?

I ask this because I did the r&r dash routine to relocate the sensor on the a/c core. Was not sure I indexed one door correctly and upon start-up, it seemed to run through a short period of air diversion between feet and dash outlets. Everything works great now. No more freeze-up's to boot.