Blend door problem, calibration?

[Catmechanic]

I'm having trouble with the heat blend door on my truck. I read the TSB but am not really sure it applies to my problem. My issue is I have either ice cold air or HOT hot air, nothing in between. I can move the temperature control one click and it will go from full cold to full hot. Sometimes it will do it spontaneously on it's own. When it's hot out my AC blows ice cold (unless of course the truck decides to suddenly blow hot air for 30 seconds or so).

Does anyone know if there is a calibration procedure for the blend doors?

 

[Gear box]

Step 1: Turn your fan to the lowest possible setting.
Step 2: Hold down the climate control/conditioning button for 10 seconds.
Step 3: Let go of the button, then press and hold it again until the lights on the button start flashing.
GOOD LUCK !

 

[Catmechanic]

Thank you @Gear box !

 

[Catmechanic]

@Gear box I tried the steps you recommended but never could get the light to flash?

My truck doesn't have climate control if that matters. I tried with the truck in run, then according, then running, and even off just as a hail Mary.

 

[Catmechanic]

@Jimmy07 would you be able to shed any light?

 

[Gear box]

Try it while engine running and leave fan speed off. Hold A/C button for 10 seconds that should put it in recal and you should hear actuators running
Good Luck

 

[Jimmy07]

@Jimmy07 would you be able to shed any light?

That button method was only good for hvac modules through 2012, I believe.
You can use AlfaOBD to connect to the hvac module (climate control in the list), and there’s an actuator calibration test.

 

[Catmechanic]

@Jimmy07 I tried using AlfaOBD this morning but I cannot connect to the HVAC computer. I attached the error message in a pic. I'm using the Kaodtech bypass, and there are no wires on pin 3 & 11 on the female end that goes to the vehicle OBD port. The male end where my reader connects does have wires at 3 & 11. I also tried using no bypass just to cover the bases but no difference as expected. Any insight?



 

[Jimmy07]

You can only connect to the hvac module if you have an MX+, EX, or vLinker MC+ interface. Any other interface and you’ll need an adapter (or physically move wires around in the OBD port). If you are using one of those interfaces, just click OK.

 

[Catmechanic]

Ah, thank you. I was misunderstanding what the error was telling me. I'm using an older Kiwi PLX so I'll order an MX+ and retry.

 

[Jimmy07]

Go with the vLinker MC+.
It’s less than half the price, and it does everything that the MX+ can.

 

[Catmechanic]

Thanks for that info Jimmy. I was able to cancel my order through Amazon and pick up the MC+ instead. I'll try the calibration Friday when the new dongle arrives. I appreciate your help, as always.

 

[Burton12387]

[mention]Catmechanic [/mention] any updates? End up having any time to mess with it?


Sent from my iPhone using Tapatalk

 

[Catmechanic]

Sorry it took me a little bit, I had to make an emergency trip overseas for a few days for work and just got back yesterday.

The new dongle (thank you for the heads up on the alternate @Jimmy07 ) came while I was away, so this morning I used it and was able to connect to the HVAC module and successfully complete the blend door actuator calibration. I then went out and drove the truck for about 20 minutes. I'm happy to report that the temperature control worked as it was supposed to. I'll continue to monitor in case it happens to revert to its old ways. But at this point I'm going to say the calibration fixed my issue.

Previously one click on the temperature dial would move the temp either all yhe way cold or all the way hot. There was no in between. I now have the entire range of temps again.

 

[flan]

What trim level do you have? I don’t have a issue but wondered if tradesman all the way up to limited have doors that need calibration.

 

[Catmechanic]

Mine is a bighorn with the 8.4" display, non-climate control

 

[Catmechanic]

New update. The calibration did not hold. I drove the truck today and it started out OK, but after about 10-15 minutes the temperature blend began doing the same thing again. Temperature control all the way cool and vents blowing scalding hot.

I'm at a loss.

 

[Catmechanic]

Another update:

Daughter had a soccer tournament 4 hours away this past weekend. On the trip out, everything worked fine, had the vent blowing on 2, and the temp set about 4 notches up from full cold just to circulate some air. Sunday was rainy and cold so the wife adjusted the temperature to 3/4 warm. At that point, the temp blend door went to full hot and stayed. It would not go to cool even after the truck was shut off. I had taken my OBD dongle, so before we left to head home I attempted another blend door actuator calibration in the parking lot, but I received an error message that "No data was received from the ECU /interface or data was corrupted". I drove 4 hours home manually cycling the defrost on and off every 10 minutes or so just to keep the windows clear (still hot).

Today I again attempted to calibrate the actuators and received the same error message. I also tried several other selections under the HVAC ECU and received the same error each time. I pulled the glove box out and the front passenger carpet back so I could visually see the blend door. This time it worked as it should during testing. I moved the temperature controls through the range and recorded gauge readings via AlfaOBD. It's to me that I can connect but not perform any tests. It's also odd that even though the gauge shows the target % movement correctly, it shows the actual % movement as zero even though I could visually verify the motor and linkage was moving.

I was able to read HVAC ECU codes and have a B11CB - Blend door binding/faulty as well as U0422 - communication error.

I feel like my next step is to replace the blend door actuator. It's easy to see but looks like a PITA to change unless I can figure out a way to easily remove the passenger footwell vent duct that runs along the bottom of the glove box. There are two bolts that I can remove but the duct still doesn't want to come out.

Any thoughts are welcome. @Jimmy07 can you possibly shed any light on the communication error?

 

[Jimmy07]

Another update:

Daughter had a soccer tournament 4 hours away this past weekend. On the trip out, everything worked fine, had the vent blowing on 2, and the temp set about 4 notches up from full cold just to circulate some air. Sunday was rainy and cold so the wife adjusted the temperature to 3/4 warm. At that point, the temp blend door went to full hot and stayed. It would not go to cool even after the truck was shut off. I had taken my OBD dongle, so before we left to head home I attempted another blend door actuator calibration in the parking lot, but I received an error message that "No data was received from the ECU /interface or data was corrupted". I drove 4 hours home manually cycling the defrost on and off every 10 minutes or so just to keep the windows clear (still hot).

Today I again attempted to calibrate the actuators and received the same error message. I also tried several other selections under the HVAC ECU and received the same error each time. I pulled the glove box out and the front passenger carpet back so I could visually see the blend door. This time it worked as it should during testing. I moved the temperature controls through the range and recorded gauge readings via AlfaOBD. It's to me that I can connect but not perform any tests. It's also odd that even though the gauge shows the target % movement correctly, it shows the actual % movement as zero even though I could visually verify the motor and linkage was moving.

I was able to read HVAC ECU codes and have a B11CB - Blend door binding/faulty as well as U0422 - communication error.

I feel like my next step is to replace the blend door actuator. It's easy to see but looks like a PITA to change unless I can figure out a way to easily remove the passenger footwell vent duct that runs along the bottom of the glove box. There are two bolts that I can remove but the duct still doesn't want to come out.

Any thoughts are welcome. @Jimmy07 can you possibly shed any light on the communication error?

View attachment 50677View attachment 50678View attachment 50679

Need to figure out the communication issue first. Any faults in the bcm?
If you clear the faults, does everything start working properly, or do they pop up again after running the truck?

 

[Catmechanic]

@Jimmy07 I checked today and I do not have any faults in the BCM. I changed tire size back before Christmas (no MIL on the dash and procedure went fine). Out of curiosity I checked the ABS module and it shows a "U0212 lost communication with steering column module" fault. Is it possible that something I did while programming tire size could have caused the communication issue? Truck operates fine, only reason this came up is I was trying to perform the blend door calibration, but cannot with the communication fault.