Wyze thermostat no power at all

Wyze thermostat has power. I verified and re trim wires to make sure they fit well. Furnace has c wore connected. Picture with old thermostat hookup (wires were plugged into the letters with the gray around them)

Swap the red and blue wires at thermostat and it should work. Ignore the actual color of the wires and label the red wire “C” and the blue wire “R” at the thermostat. The person that installed your system has the furnace wiring done in a funky way.

Have you verified with a multimeter that you have at least 24VAC between Rc and C at the thermostat?
Check the fuse on the furnace board, and make sure the furnace front panel is closed.

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Yes, this is why you make your wires with the stickers so that they go back on the same connection points they came off. Really need to ignore wire color as that can be misleading.

I’m not sure what is going on there with the wiring. You have RED and Blue Wire on the same C terminal, and what is that fatter RED wire going to? C is common, so think of it as ground. Where is the power, Rc? Because it looks to be going to the same C in the furnace. That’s going to get you zero volts. So of course it’s not powering up. I’m not sure what is going on without looking at the wires. Going through them and seeing where they’re going off to.

With a Volt Meter, you should get 24V AC from RED to Common. This is what is going to power up the thermostat. It may not be exactly 24V, but close enough. If you have nothing, something with the wiring is not right.

A thermostat is pretty basic. It takes the temp. Then open or closes a relay. Old school using Mercury switch on a heat senative spring to make a connection.

Yellow is cooling for your AC. You can manaully jump the yellow wire to the red wire and turn your AC on. The green is for the FAN to turn that on and off. Same there. Red wire jumped to green wire will turn on your fan. Heatr is normally W. White to red will start up your Heater. Hold red to white and green and now your heater is running along with the fan.

You cna also have more than 1 state. Our AC units at work, some have 3 or 4 compressors. So Y1, Y1, Y3

RED is power. Your thermostat will just make a connection from the Red wire to the Y or W for Cooling or Heat, and then Red to the Green to turn the fan on/off. That’s as basic as it gets. The main control board really has all the smarts. You call for heat, and the main control board will go through all the steps needed before it fires on the burner.

If you don’t happen to have a voltmeter, go to Home Depot and pick one up for cheap. They can be used for all kinds of things around the house or on your car. Watch some youtube videos on how to use a voltmeter. You may be at a point where you need some pro help. He or she can go through the wiring and see what is wrong and fix it. It shouldn’t take long. A little labor. But from what I see, it looks like the red and Blue wires are BOTH on the same C terminal on the mainboard. How does that work?

Look closer, the red on the C terminal with the blue is from a different cable than the thermostat cable. I think it’s in the cable that goes to the AC condenser.


I blew a fuse. The wiring and everything was correct. Thanks for the feedback everyone :+1:

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The wiring looks fine, they have an A/C compressor hooked up to C and Y like they should have.