You must have a splice somewhere where a past technician or homeowner decided not to connect the blue and brown wires. You could try to find that splice… or I can show you how to hook up the c adapter.
If you hook up the C adapter, during setup, tell the wyze app your old thermostat has the following wires:
Rc, G, Y, O, W
@speadie Any chance you might be able to help here? It would be greatly appreciated!
Standard G, Y, W, R at the thermostat.
I’m fairly certain that the lower right terminal with all the wires attached and the large yellow wire is C.
Your wiring diagram with a C adapter would look something like this:
You have 2 splices that are wrapped with electrical tape and hopefully contain wire nuts, for W and Y.
The only wires that you interrupt with the C adapter are the ones that go to the thermostat, all other wires should stay where they are.
Note that the green wire goes to G on the C adapter and C on the wyze.
For the initial setup and if you ever reset the thermostat and need to set it up again, use the following wires in the app when it asks you about your “old thermostat” :
Rc, G, Y, W
If you wanted to add a fuse, it would go between the R terminal on the board and the R connector on the c adapter.
Oooooooof - Speadie - got me going in circles over here! 
Before I light something on fire - I unwrapped those connections and got confused.
With this new picture - can you confirm your wiring diagram to make sure I am correct?
The W & Y is what is throwing me for a loop - previously covered by the electrical tape.
looks ok. Y and W used to be on the same terminal board that the other terminals were on, but they must have pulled off at some point. You’ve got the thermostat’s R and the G wires in the air connected to nothing.
Y going to the thermostat is the thin Yellow wire, the other red wire attached to Y goes to the AC compressor contactor.
W going to the thermostat is the white wire, the other black wire attached to the W terminal probably goes to the furnace sequencer.
The C terminal has everything that runs off of 24V in the furnace connected to it, as well as a wire that goes to the other side of the AC compressor contactor.
The red circled wires will be attached to the C adapter’s wires. the white and yellow wires will be attached to their respective slot in the C adapter’s terminal block.
No need to pay me, but thanks for the offer.
Are you sure ? You have spent a ton of time helping me alone - least I can do is get ya some dinner! If you change your mind - feel free to DM me
[MOD EDIT] Removed personal email address from the forum and replaced with DM
Confirmation overall on this though - going to run through it tomorrow.
The left red circled wire will connect to the C adapter Ribbon Wire “W”
The right red circled wire will connect to the C adapter Ribbon Wire “Y”
The rest of the Ribbon Wires will connect to the R, G, & C Terminals on the transformer
The R, G, W, Y Wires coming off the thermostat wire – will connect to the C adapter posts in their respective order.
End product looking something like this:
I have experienced this kindness as well. I offered to pay for parts but the friendly member declined. Some people are definitely not here to make money and offer their time for free. It is good to see such compassion.
