When I bought my Excella from the PO, he told me that the AC was not blowing cold air, just air. He said it would be fixed before I picked up the unit and felt it was low on freon.. When I arrived he said that no one wanted to work on the unit and was told to just replace it. I brought it from AZ to TN and enlisted help from a friend as we both poured over the service manual that came with the unit. He checked the freon and found it to be just a little low, not enough to keep the compressor from starting up. I checked the thermostat and jumped across the terminals as stated in the manual. Nothing doing. I measured for current and could not find anything within the thermostat. It should have shown 24 volts DC. Checking on top of the AC unit I found that 125 volts AC were coming into it. A transformer on the street side of the unit was supposed to send out 24 volts DC to the thermostat but was only showing 9 volts. Hmmm. I found a new 125VAC to 24VDC transformer at an electrical supply house, bolted it up. As soon as I turned the AC on and the thermostat to 65 degrees the AC compressor energized. That humming was sweet to my ears. A $15 fix beats a new AC any day. Get a service manual and test your unit without frying youself. I can't say it is as easy as my problem but who knows. You heard right, the Armstrong was built to commercial standards and is tough.
'01 2500hd ext. cab, 8.1 litre gas, 5 sp. Allison auto
3.73 rear end
Mag-Hytec rear diff cover
Amsoil Dual by-pass oil filtration system
Amsoil synthetics all around
265 watt AM Solar, Inc. system