I'm in a dire situation while struggling to keep cool in the Texas heat (luckily it's not summer yet).
Our outside unit stopped working all together 2 weeks ago - compressor and fan would not turn on when calling for cooling. At first I thought it was the contactor; however, after replacing the item, it would still not energize after calling for cooling. When I press down on the contactor, the compressor & fan would start right up on the unit (although it produces a TINY spark when pushing down, ultimately going away).
I then measured the wires coming out of our house, and noticed I was not getting 24 volts to the unit. I am however getting 240v AC to the other side of the contactor.
This lead me to looking at my control board on my air handler within the attic, but I'm not even sure where to start. I checked the condensation pan, but it is completely dry. Could it be possible that the transformer is not sending 24v to the unit? I checked the fuse on the control board, but it is completely fine. Would I need to pull out all the connections on the transformer to check for continuity / ohms on my multimeter? I noticed that it has two yellow wires, a black & white one, along with the purple wires on the bottom. I'm not even sure what they go to, or how to test this, to be fairly honest. What else could be the problem? The thermostat does work and has new batteries.
Please bare with me, I have never troubleshooted on a control board or had this issue before. I am eager to fix this issue and save on costs - sleeping in 83+ degree weather is getting a bit too much for us.