Heater not blowing hot air SOMETIMES.

Mikerizer

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#1
Make
Dodge
Model
Grand Caravan
Year
2006
Miles
85,000
Engine
3.3L
To preface, there is a coolant leak somewhere, but I haven't had time to do a pressure test. The hoses going into and out of the heater core are hot. Sometimes the interior fan blows hot air, sometimes it's stone cold. Is this likely a blend door problem, and is it actuated by electric motor, or by vacuum?
 
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#2
Hey how are you doing?

OK this is a 12v actuator, on driver side of HVAC unit, Before tearing it up, try calibrate - there MAY be a youtube tutorial so google and look but procedure is attached.. other things I would at bleeding all air in coolant, a open thermostat, .
 

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grcauto

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#3
Try a system relearn.
For non vacuum operated systems (electronic) the module needs to learn the full open and full close positions of the doors.
AC reset
Turn the system on full cold Max AC.
Radio OFF.
Turn ignition OFF.
Pull the HVAC (AC) fuse from interior fuse box. Leave out for 1 minute and replace.
Turn key to run/on position....NOT start.
Do not touch any controls. You'll hear the doors (actuators) being opened and closed. The HVAC module is learning the full open and full close positions. Wait until the system is completely done with the learning process. Less than a minute.
Start and test the system.
 

Mikerizer

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#4
Will try that; thanks! This is the same van that the cruise control was not working for over two years, and I had to disconnect the battery overnight while waiting for an EGR valve to come in (I had to move the alternator to get to it). After that, the cruise started working!
 

kev2

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#5
SECRET When dealing with chrysler products, removing the IOD fuse or as you did the battery the system reboots- will reset most BCM functions - wipers, cruise, lights, as well as dumping codes...

how many wiper motors are replaced in the northeast CaChing

Did you find a you tube tutorial a picture worth 1k words....
 

Mikerizer

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#6
I think this is fixed. I tried the relearn by pulling the fuse, but I'm not sure I was trying the right fuse. I found some instructions in another forum: turn key on with AC on full recirc, then press and hold the recirculate and rear washer buttons at the same time for about 5 seconds until the LEDs flash. Wait about 2 minutes while the blend doors move back and forth, for the computer to learn the open and close positions.

I am, however, starting a new thread for another problem...radiator.
 

grcauto

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#7
I think this is fixed. I tried the relearn by pulling the fuse, but I'm not sure I was trying the right fuse. I found some instructions in another forum: turn key on with AC on full recirc, then press and hold the recirculate and rear washer buttons at the same time for about 5 seconds until the LEDs flash. Wait about 2 minutes while the blend doors move back and forth, for the computer to learn the open and close positions.

I am, however, starting a new thread for another problem...radiator.
There are different procedures. I must have gave one for a different year.