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I've lost my AC and my blower motor for heating/cooling

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Any ideas on a likely culprit for losing my air conditioning and my heating and cooling controls on my 2012 Boss? My defroster and fan controls are inoperative as is the AC. The lights on the panel work but no air comes out of any of the vents. I went through the fuse blocks and tested everything related to the system with both a 12 volt test light and a multi meter. All fuses are good. I don't know how to test the relays... I'm zeroed in on the blower motor resistor but I don't know if that's correct or not. I have power to 2 of the 4 wires confirmed with the 12 volt test light. Anyone seen this arse ache before? Thanks all.
When you find the culprit it will likely fix all of them.
Going to my wayback machine and the blower relay, I think ( I think) on these cars the relay will control most or all of those, it might also be that all of this runs through the high blower relay, and when you lose it, you lose everything. Dig up a wiring schematic and start doing some research that way, also you may have an inline fuse in there someplace. I've been working on every mustang since 1964 and quite frankly, at my age some of that runs together these days. You may also want t to look at some of the can/ bus stuff, but you're past the first step of checking the fuses, time to look at a schematic.
Yikes, I just looked at some wiring diagram online. While I don't have the IQ of a turnip I know when to surrender. I'm simply not adept at reading those and comprehending them. I'm thinking my local Ford dealership may have seen this movie before.
Well Blacksheep, Thank you!!! Thank you so much sir!!!. Don't discredit your memory. I checked all the fuses and swapped some relays. All good. Autozone would allow a return on the blower motor resistor they had in stock so why not. Bought one, plugged it in and damn, it's fixed!!. Thanks to all for weighing in. Saved me a trip to Ford. Now my baby is 100 percent again.

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