Thermostat with external transformer

Is there a Blue thermostat wire at the air handler/AC? it might not be connected to anything.

Yes you are right. it’s not connected to anything. Got my hopes up when I saw it but no blue in the handler. Just this:

I tried the adaptor wyze gave and my handyman gave it his best shot and we still failed.

do you have a wider shot of the board, with more wires in view?

is this any better?

where does this blue wire go?
the one that comes out of the thermostat wire bundle

Man, you have great eyes to spot that. :slight_smile:

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It goes to HEAT on the board.

here is the zoomed in shot.


Your image shows it goes here.
Which is to say, it’s unconnected, so strip back the insulation a bit and connect it to this C terminal with the white wire that goes to the common side of your A/C compressor contactor:

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Bro you are a genius ! I finally got time to try this out and it worked on the upstairs thermostat. Will try the one downstairs tomorrow. Wyze support said the units were faulty :laughing:

Thank you again so much !

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