2009 Charger AC/Heater control question

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snapetwo

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Ok, first I know its not an A body, but rather then create a new account on a charger forum and you guys are hella smart.

SO, 2009 charger has manually knobs to control the AC and heater, yet the manual knobs connect to an electrical harness, so there is no cable linkage.

My question is, how the hell does this work?
If I turn a manual knob, and its connected to a wire, and this knob controls fan speed, how does it know what speed I am selecting?

I'm assuming here that the knob is connected to a potentiometer and that the resistance changes, and that affects the fan speed. Makes sense.
What about the temperature? or the heater vent zones?

Does the variable resistance determine how far cool air/hot air baffles are open?
Does the resistance determine what zone is used, somehow?

My reason for asking this is, I am putting an ipad into my dash, I have to relocate the big clunky manual AC/Heater controls to make room....id rather have the Ipad control the heater...

So that's what I'm getting at, If its some kinda resistance setup, perhaps something like the Arduino computer I've read a little about, could be used to talk to the heater and the ipad?

Anyway, any information would be greatly appreciated.
 
Switches talking to computers talking to motors talking to blend doors.

Nothing is as simple as it once was and unrelated components can be tied together.

Engine management tied to climate control..... Sounds crazy but it can and does happen these days.

My suggestion would be to change your plan.
 
Yup fancy little servo motors instead of vacuum servos to operate the plenum doors.
Many will direct blower to heat vents on only after the water is warm.
Relocating the controller might be easier than relocating a old school mechanical controller. Operating it with another device would be a challenge.
The ECU changes the engine signals automatically when the a/c compressor starts.
Interrupting those type of communications could cause minor or more than just minor issues.
Worst case scenario "Ipad works great but engine wont start/idle"
 
All goes throught the BCM (Body Control Module) Your input is just a suggestion to the system that you would like the ac on so you can cool off.
 
Interfacing an with an ipad is much more difficult than using an android tablet. Androids are open system. Some newer vehicles have the A/C controls under the CAN interface, and can be reached from OBD2 connector with special software. Much of this is proprietary, and is used for test and development. The tools and software are often dealer only, or very expensive.

The knob controls may be special and closely related to the control board. I doubt they are potentiometers, those are rarely used anymore. More likely switches, the control keeps position in memory, and responds to changes.
 
Hmmmm....
I gotta believe there is a way to make this work (aside from the ipad programming part, so unrelated).

My thinking is, if I can just figure out how exactly the heater/ac control knobs work, I can put something in its place. kind of like a "man in the middle", make that device send the same signals....and then no ECU in the car has to even know that the stock controls aren't telling it what to do.
Im thinking, if I can get this arduino (whatever it is) to work or something similar, and it can mimic the same output signals/resistance/whatever as the stock controls...it will work. Then its just a matter of getting the Ipad to control the other device...wish it was open source like a droid, but im an IOS guy.

really dummied down example, If you take a toaster and plug it into the kitchen outlet, it works....if you take the toaster and plug it into the outlet near the bathtub it will work just the same...cuz the toaster doesn't care, its getting the same power/signal to make it work.
Same premise on this idea, I hope.

Think im going to have to buy a heater control off eBay, tear it apart and see what I can see.
 
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