First, most /all control transformers are fused, some of them "not obviously." On many (including battery chargers) you can carefully cut into / unwrap the first layers of paper on the transformer, and there's a thermal protection device under there. This is a combo fuse and thermal device, if the transformer gets hot, it will pop
SECOND. IF the transformer blew, "something" caused it. There are LOTS of causes most simple. There could be a "raw" spot in the stat wiring grounding / shorting on ductwork/ piping / a nail. Easy. Cut it loos at both ends and check it with a meter for continuity and shorts
THIRD. "A load" in the controls circuit could be a problem, or othe related wiring. For example, the coil could have gone bad in the contactor in the outdoor unit. "Some" of the wiring might have a problem. It's not unheard of for mice or other rodents to chew on the stuff
"The weird thing" you say the fan works. The fan control circuit SHOULD be using the same transformer, wiring, and so on as the OD unit.
DOES IT HAVE two transformers? Some units have one in the furnace (indoor unit) and a second in the OD unit. Many use one for all the controls
A little "film" on internal transformer protection
Then unit has 1 transformer that I see.it have a manual switch I can turn my fan on inside the unit..I switched out the thermostat and still nothing..I'm thinking it's the wires the go from the unit thermostat wires ..but no sure..there is no fuse in the wiring as of now but will be when I'm done..
