We were getting the E1 error on the bedroom stat. I read a lot of stuff on the net about fixing this. Our Dealer, sent his Tec to our House to fix the problem. ( 275Km round trip) He brought a thermostat that he removed from a new trailer. He replaced the stat and got the E1 then he disconnected the right hand wire ( power wire) let it stand for 10 minutes. when he re-connected no error until he put the face plate back on. He then got the E1 again. He repeated the the disconnect but did not put the face plate on. Instead he just touched the bar that would plug into the face plate on the "Mode" side button. The screen light up, he toggled through the settings and the AC came on. We have been using the AC on holiday for a week since. The Tec said he would order a new thermostat.
I applaud our Dealer in Rosetown for saving me a trip with the trailer and having someone who can think outside the box