The Heater and Fan will come on my itself , and you can not turn it off. the ATC unit has no light on it. I ran the ATC diagnostic after I turn the car off and it displayed a 36. Is this code telling me the the ATC unit is Bad??

Code 36 is "ATC head communication failure"

Before spending a ton of money on a new ATC head (Automatic Temperature Control computer), try removing the trim piece right above the glovebox, it snaps into place, and looking at the inside temp. fan. Its a little fan that draws in compartment air to get a temperature reading. A lot of times, this fan gets thick with dust/dirt and causes an ATC malfunction. To clean it, remove it from the dash and wipe clean....try that first. If you still have a communications problem, the ATC has an internal problem & be prepared, they ain't cheap.

I have almost the same problem in my 94 intrepid. While driving, all dash gauges shut down, air bag light comes on, heat comes from the defrost vents full blast and the traction control light comes on. Sometimes when I apply the brakes firmly everything returns to normal. If not, the car must be shut off and then started again for everything to return to normal. Weird!!!!

In your case Drac69, it sounds like you have a loose bulkhead connector. If you want, look underneath your dashboard and see if there are any loose wires going from your firewall to the rest of the car. That would cause your gauges and everything else to act up.