[xile6]

Yes and no. Jumping the wire is kinda bad because if it doesn't get turned off at the right temp it will ice and leak like you said. I would keep that intact.
On the digi temp setup yea its possiable and you r on the right track.
So it all can be don't just some wiring to do. And you need a good temp switch

 

[xile6]

Yes the blower controls is just a set of resistors, but that same control also loops back into the compressor to cylce it on and off depending on what the blower motor is set to. I.e. fan on 1 might mean 75*, fan on 4 might mean 60*.
But as far as the evap temp switch goes. You first need to find out what is the lowest
temp that it trips at. And then you will go up from there. If the evap gets down to 40* before it trips the thermostat, then you need a switch that will trip at 40*. Then you would adjust up.

And it all depends on the temp switch. If you have one that outputs at a programed temped then yes. I.e. you set it for 60* and when it hits 60* it outputs a ground(or power). Then you could use that to trip a relay for the thermostat, it would then cut off the ac compressor till the temp with up.
The only thing with doing it that way is you will get a false temp. The evap is much colder then the temp out the vents. So setting it to 60 might mean 70* out the vent. It would take some getting use to and they would have to be an override so the temp doesn't get set to low.

I could probably help with making the wiring. Its just right now I'm replying from my cell so I'm not at home with my diagrams and software.

But just know fan controls are tied into temp on the civcs.


*edit
Also explain what all u want from this system. Could be over thinking the whole thing.
If your wanting to hit ac and set temp. Then all you might need is just a digital temp controller and some relays
The ac would be wired up that when it come on the fan spend would be 2 and then you set the temp and it will blow out cold air till that temp relay is triped. Then it could cut the compressor and just blow out air till the temp goes up, then the compressor would kick back on. Migt need a time delay so the compressor wouldn't be cycling on and off to fast.

 

[xile6]

not a 100% sure on how everything works. Didnt get to much into the ac wiring. But on the fan speed controls, they just us a different resistor to ground to change the speed.
easiest thing to do would be to leave the system stock. Then add your digital temp control to the ac clutch. So once the temp you set is reached then it would kill power to the ac clutch. Once teh temp inside goes up your digital temp control would feed back power to the ac compressor clutch wich it would then start bad to cold down everything. While all this is going on the fans would stay on.
And the ac button itself would be relay into your controller so that when you turn your controller on jumps the stock ac switch on the cluster.

For heat either live with sliding the cable or find some kind of motor that would work. and the heat would be a different circuit. It would have to turn off the fan speed when the temp got to high

 

[xile6]

I believe the fan is just controlled by resistors to ground. It cuts the compressor off by temperature. i.e speed 1 would more very little air so the evap would stay colder. Vs fan speed 4 which moves a lot more air but also warms up the evap.

Best thing to do is going to be to get your system up and running and then do some checks. But to get what you want its best to piggyback off of the stock system, then make a whole new one.

 

[xile6]

dont know to much about transistors. Just found out what they can do a week ago when i started to make my push button system. But i do know that they have 3 legs. 1 and 3 are normally a pass through and 2 is what controls if it passes through or not.

And to tell the truth it might just be easier to go to the ac switch on the ecu. I believe it outputs a ground when the compressor is suppose to run. So all you have to do is relay a ground in there with a diode. So when your temp hits preset it breaks ground and turns off compressor. But im just not 100% sure if this will work at all times.

But what would work at all times. Would be to cut the ac switch button. and relay that. So when your temp is reached it would be as if you just pushed the ac button which turns off the compressor.

Then blower speed would have to be a Rheostat that could hold 30/40A. Or just keep the 4 factory settings. Use a turn dial that would work like a dizzy cap and rotor. Each cylinder would output to a different speed. And the rotor would be the main ground. get what am saying? I know how it is in my head but putting it into words is a little hard.