Heater control/blend door

TomDabb

Member
I recently replaced my HVAC control unit as well because it had lost a lot of its functionality, when I installed the new one the light for rear defrost blinked and you could hear the blend doors moving around, it was calibrating itself which it sounds like yours cannot do which leads me to think you are on the right track with checking the actuators for proper movement. Good luck.

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Thanks for your thoughts Clark - I’ll know this evening and share findings


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TomDabb

Member
I would disconnect the battery, negative first and then positive. Wait a minute or two and reconnect. That should reset the ECU:

https://www.quadratec.com/c/reference/jeep-ecu-electronic-control-unit-reset

Then test. It might be as simple as resetting the system.

Disconnected the battery today - hoping it would be very simple - no joy.
Still only full heat or full cold. Nothing in between.
Tomorrow going after the blend door and motor. It’s gotta be that. Wish me luck!


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TomDabb

Member
My heating issues is not completely resolved....
The blend door motor arm, the white plastic one, moves completely smooth through its full range of motion - it just doesn’t stop anywhere between both extremes - all hot or all cold.
Any help would be greatly appreciated as this is getting to me. But stubborn as I am - it won’t get the best of me!


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sipafz

Caught the Bug
My heating issues is not completely resolved....
The blend door motor arm, the white plastic one, moves completely smooth through its full range of motion - it just doesn’t stop anywhere between both extremes - all hot or all cold.
Any help would be greatly appreciated as this is getting to me. But stubborn as I am - it won’t get the best of me!


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Did you get a new actuator or are you still testing the old one?
 

sipafz

Caught the Bug
I haven’t gotten a new actuator - I feel like it’s working


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Do you have a standard control unit or a climate control unit? You mentioned that you replaced the control unit. I’m assuming that you replaced it with the exact same thing? Is the replacement Mopar or other?
 

TomDabb

Member
It’s standard three dial control. Yes, mopar unit.
I was able to stick my arm up and threw all the wires and feel the actuator arm moving to the full extents.


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rmilobrown

Member
Hey TomDabb, did you ever get this sorted out? I ask because mine was still full Hot or full cold! I put it on the back burner and was ready to try a three knob controller. When I installed my lift, I had the battery disconnected for a couple of days. After reconnecting, problem went away! More than a week now with full temp control! Go figure! I had read about the computer reset after changing the BDA but didn't disconnect the battery for more than a second. Maybe it needed a longer pause, OR the problem is intermittent and will be back.

HAPPYTRAILS
 

TomDabb

Member
Hey Rmilobrown - thanks for the feed back. Yeah I tried the battery disconnect twice. Second time about 30 mins. No joy.
Everyone I run into w a JK, hasn’t had this exact issue - so I’m still thinking - WTH.


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TomDabb

Member
Hey rmilobrown,
I haven’t solved my heater problem. Is your control still working thru the heat-cold range. Mine is still all hot or all cold. No one has any idea.


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rmilobrown

Member
Yes, mine is still working. About 600+ miles now gtg. I never found a detailed answer why full hot or full cold. There is no limit switch on the bda or the blend door to tell the controller to stop. If you plug the bda in without mounting it, it will travel almost 360. I think the controller sees the current pull on the motor when it hits the extreme hot and cold stops. I first thought maybe the aftermarket doorman unit had a slight different motor than stock. After reading many posts, someone mentioned the controller not able to calibrate any longer. I did talk to a Chrysler mech about, he said " It's plug and play" Great. If nobody has an answer, I would have tried a Mopar controller with a Mopar bda. Good luck!

HAPPYTRAILS
 
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