Thermostat, No C terminal on "control board"

Hello! I have a pretty old combo heat and AC unit on my roof. I didn’t have a c wire so I went up to find the control panel and I’m only seeing 4 terminals r, y, g and w.

Anyone have an idea where or what I should do to get the c wire adapter connected correctly?

Thank you!

Here are some pictures:

Maybe something like this would work if I plug it in in the attic and run the wire down with the existing thermostat wires?

Your 2nd picture shows the 24v transformer, trace the wire from R terminal back to the transformer. The other wire on the transformer will be the C wire, trace that wire out to see where it connects. Worse case you can cut that C wire, strip it back a bit and use a wire nut to connect it back together with the C wire adapter. If you go this route, make sure you turn off breaker just to be safe.

1 Like

Is there another screw terminal right here?
Is that blue wire available at your thermostat?

If so, connect the blue wire to this terminal and to your C terminal on the wyze.
Your thermostat wiring needs to be re-sleeved or insulated with electrical tape, the insulation is pretty compromised.

Thank you so much! I went back up the roof today and was able to get it all working with your advice!