my Ac is on no matter where the thermostat is. For heat it’s cold and the ac clutch comes on. So no heat at all

 

After engine is warmed up, open the hood and feel BOTH heater hoses at the firewall.
If both are warm/hot then heater core is OK, if one is much colder than the other then heater core is plugged up


If both hoses are warm then Blend door is not working, common issue on Fords

Google: ford ranger blend door

The temp control opens and closes the Blend Door, that is all it does.
Yes, AC Compressor will cycle on and off all the time, it is used to dry the air in the cab, summer or winter, temp control doesn't effect AC one way or the other
AC is either on or off, it has no temp control, if you want less cooling the temp control opens the Blend door and mixes heater core air with AC air which warms it up, making is less cool

Blend door covers the heater core, so when it is closed(COLD) then no air from the fan passes thru the heater core, as you turn the control to HOT an electric motor(actuator) opens the blend door letting some air pass thru it, at HOT all air passes thru it.

Most common issue is the electric motor dies
But the tip or the "bar" on the blend door can break off, thats the part the motor turns to open and close the door, then whole door needs to be replaced.

To replace the Blend Door or heater core you pretty much have to remove the dash board, whole thing.

But watch some of the videos there are ways to fix it and even change it(blend door) without pulling the dash