I posted this in the General Tech forum a few days ago but no help as yet. It was suggested that Classic forum might be better, so here it is. I hope someone here can help

Anybody know the design set points for Cut-Out and Cut-In temperatures for the A/C thermostat (icing switch) for a 70 Mustang/Cougar?

In checking the A/C system components I found the switch not functioning (not opening in an ice bath). Working with the adjustments I was able to restore functionality. I've guessed at a 40F cut-out and 50F cut-in.

Since the switch function is to prevent significant icing of the evaporator, and the thermostat probe is predominately in the air stream seeing warmer temperatures than the coil surface 40F seemed reasonable for the cut-out. The cut-in should be enough higher to allow reasonable cycle times but not loose too much cooling, that's where the 50F guess came from.

The Ford shop manual calls for testing the cut-out using salt with an ice bath at 25F. I presume that is for quick response to the test (if the air stream gets to 25F the coil will be a block of ice).

I'm sure the actual switch set points are a bit different and would prefer to re-install the switch with the proper set points.

Can anyone help me with this?

Thanks
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A Mustang cousin - 1970 Cougar XR7 - much in common