I have a Goodman Janitrol furnace and I am needing to add a C (common) wire, for the newer thermostats. I would like to avoid the substituting G for C, and just run an additional wire.
I have read several post that suggest to use one of the Blue wires coming from the furnace transformer. I have attached pictures for reference. In picture 1, you can see that I have two blue wires and one green wire (which I'm assuming is still part of the blue family), one red wire, one white wire, and one black wire. One of the blue wires runs from the transformer to the switch (which says ON), the other blue wire goes to the board, and the green wire goes to a ground bolt.
Which of these wires would it be best to connect the C wire to? If I connect it, is there any potential electrical issues that could occur? Lastly, if I connect a C wire to one of the blue wires (or green), can I then just run that wire straight to the thermostat and plug it into the C-labeled connection?
Any help would be much appreciated, if you have done this successfully please let me know how you did it.