The plot thickens. Airstream is now saying that the bedroom temp sensor is under the street side upper storage bin on the 26u. I had originally looked there, but looked again to make sure. I have received a replacement sensor from an online vendor, but AS insists that I have the dealer correct the problem with the original sensor. I figured out an easy way to solve the problem by routing the new sensor thru the ceiling and down into the corner of the bath. There is a trim piece in the corner of the bath that would be ideal to route the sensor wire behind and exit into the bedroom. There would be no inner skin to remove and it would be an ideal location for the sensor. But AS was insistent, so I have another appointment on Monday.
I think now that there were 2 problems with the rear sensor. One, that the dealer found on the first visit, being a bad sensor wire connection that came loose on out maiden trip. The second is the sensor itself stuck up inside the ceiling.
The dealer, Vogt RV in Fort Worth, has been very understanding and is trying to solve the problem. At least, I am developing a relationship with everyone at Vogt!