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Need help to control HVAC system

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  • Need help to control HVAC system

    I am looking to buy a fusion Brain and program it to control my HVAC in my car (old car 1991). Does anyone have a turtorial that can help, or can anyone point me in the right direction of how to start? I have never done anything like this before...

  • #2
    That will really depend on the car. What model is it? What kind of HVAC controls are there. If you take out the HVAC unit are there cables connecting everything, or is it all electric controls. What do you want to be able to do with the finished system?

    In my car, I've removed the entire hvac control panel and will be using the fusion brain to control all the stock buttons, with only the original display remaining.
    Old School member!


    • #3
      Its a 91 Camaro. They are all cable driven, and the temp selector is a cable driven system, so I would need to control a servo motor or something like that...


      • #4
        Keep it manual. You can upgrade to automatic later. Chevy Lumina vans had an electrically controlled vacuum manifold for controlling the direction doors with the FB. I also picked up an Audi actuator to replace the cable operated temperature door. This unit had a built in variable resistor to provide position feedback. The FB can operate relays for the fan speed.

        Software look at setting a variable for each instance. For example to control mode 0 is off, 1 floor, 2 vent, 3 defrost, 4 blend.


        • #5
          Ok, so keep the temp manual for now, but use realys to adjust fan speed, then with the variable instance for control mode, how is that hooked up, is that relays, or are there specific outputs on the FB that I can program to output the voltage to change the mode?

          This is all new to me, but the info you've given me so far is very helpfull! Thanks!!


          • #6
            Your Camaro has vacuum actuators for the mode doors, thats where the Lumina manifold comes in. The FB will control the manifold with small relays. Your fan has fixed speeds, more FB controlled relays. The AC request, FB controlled relay. The temp door is a cable. This is converted to the actuator which is controlled by the FB with...wait for it...two more relays. The variable resistance in the unit I picked up allows the FB to keep track of where the temp door is. Everything else is on or off.

            Manual I was referring to was in the software not trying to come up with an elaborate auto temperature program straight away.


            • #7
              lol I got ya. So the key word of the day is... Relays. I get what you mean now about manual. Thanks again for your help. As soon as these boards become available I am gona start working!