Both AC's had worked just fine B4 I left Texas. This was a new problem that developed while in Colorado high altitude. Sorry I didn't clarify that sooner.
I switched the sensors this morning and as soon as I turned on the front AC on which was the unit I put the bad sensor in gave me an E5 error which is open ckt or out of range freeze sensor. So far the back unit is working as it should.
I pulled the bad sensor out again and sure enough it was open ckt when I checked it with a VOM meter. I wish I had checked it before I sent to the trouble of installing it in the front unit.
New sensor on order.
Thanks everyone for you help. I know just enough to be dangerous on things like this.
I am getting too old for this kind of stuff. Four trips to the roof! Yuck.