under dash harness

First order a wiring diagram from classiccarwiring.com for your car.
Or
You can download your cars Factory Shop Manual from MyMopar.com or even maybe a wiring diagram alone. (MyMopar.com is free download)

Then start tracing out the wires for each setup and see if you can repurpose some wires if need be.

You might need some plastic connectors if they are different from AC to non AC .