10 year old Duo Therm 15k unit on FW only blows hot air. There is 120 AC power to unit, and thermostat seems ok, and DC 3a fuse ok, and blower fan work.
Anything to do/try other buy a new upper unit?
2003 Sunnybrook 30RKFS
2003 Chevy Silverado 2500 Diesel, Allison Transmission