Heating Controls And A Carputer

[electric_monk]

For years now I've been wanting to install a carputer in <whatever car I had at the time>, and currently I have a 2001 V6 Ford Mustang which I love. However, the screen I procured is a little larger than the stock head unit, and the gearstick is kind of close, making everything a little cramped. I've recently had the notion to replace the heating controls with something the carputer could drive (I'm okay at electronics and building things), so I was wondering if anybody knew anything about the behaviour of the air conditioning.

Basically from what I've found online there's three parts to the controls - the fan speed, driven by a resistor network, the temperature, controlled by a cable that moves the heater core in and out of the stream of air, and the mode selector, which turns on/off the fan, A/C clutch and connects various vacuum lines to the engine vacuum to move various baffles in the airflow around.

I found an image online which seems to correspond with what's behind the Mustang heater controls indicating which colour vacuum hoses control which baffles, and it seems to me I could actually improve the controls over what Ford installed (e.g. separate recirculate/external air control, more control over where air goes) as well as use the carputer to implement climate control quite easily.

Mostly I'm just wondering if anybody with experience of the Mustang heating system has any input - is this even correct (I've not actually taken my dashboard apart yet, merely consulted the Haynes manual/online resources) and also, if anybody could recommend a non-Mustang part I could use to control the vacuum? I'm no car expert, but I understand other vehicles have similar vacuum-controlled systems that provide climate control and so have an electrically operated vacuum solenoid that'd let me control that part, ideally in a way that would "just work" with regards to whatever connectors are already there (ideally this would all be revertable).

Regarding the other parts if anybody is interested, I intend to operate the fan directly via a chunky transistor, the A/C clutch with a relay, and some sort of geared electric motor to just wind the temperature cable.

Thanks!

 

[BlownFiveLiter]

I don't know how good you are with coding and electronics, but I would bet you could do something like you're planning with an arduino unit for the climate controls. The easiest way to do it would probably to retain the factory controls and use a servo on them, controlled by the arduino, or the carputer if you're capable. Personally, I wouldn't understand any coding language any better than I'd know Chinese, so I'm definitely not the person to consult on that. Just thinking off the top of my head.

 

[electric_monk]

That's mostly what I'm thinking - there'll probably be some control box between the carputer itself and whatever form the heater control replacement takes, although I'll probably build it from scratch. I'd considered just controlling the actual controls internally, but I'd really like to replace them, as doing so will give me more control (e.g. being able to control the parts in the airflow will give more control than the current dial allows), which is neat if nothing else

For reference of similar stuff I've done before, here's a video showing a circuit I made to control the satnav hood in an RX8 (my last car, which I owned back in the UK but had to sell before moving to the US - the hood had had all the electronics pulled so all that was left was the electric motor, so I built a circuit to allow the computer to control it via USB):