Thanks that was it. I just bought this newly remodeled mobile home and it appears they replaced the t-stat. It does have the cool/heat switch. Would it be wise to order a new one or just operate it in the heat mode all the time? Also, as I was trying to figure out why the A/C was running all the tim...

I have a 2-wire A/C control box # 7900A6021 running a coleman evcon presidential furnace system. When I switched to cool this spring the blower automatically kicked on and so did the outside A/C unit. As long as the Heat/cool switch is toggled to cool the unit runs all the time. The outside a/c cont...