2 wires in Y, should I put both in C wire adapter?

I’m installing the c wire adapter in my furnace and I have a yellow and an orange wire in Y. Should I put both of them into the adapter or a specific one?


One of wires on Y most likely is going to the condenser, the other to the thermostat. You’ll have to trace the wires to verify which one is going to the thermostat. That wire will be the only one that connects to the adapter

Make sure you actually need the adapter. do you have any unused wires on your thermostat run?

if you in fact do need it, then only the wire that matches the one you have in your thermostat should go into the adapter, the other one needs to be left alone.

Thank you both for the replies. @Ken.S I don’t know if I’ll be able to trace the wires. They both are in the same sheath that goes directly into the wall. Would it be a bad idea to try one and see if it works and if not try the other?
@speadie I don’t have any extra wires that are run to the thermostat. Other than that I was just installing the adapter because the app told me I needed it. Here’s my wiring situation at the thermostat if it helps.

Can I get a wider shot of the furnace wiring. Looking to see what wires go into what bundles.

You bet. All the wires that are screwed on to the board go into the brown bundle.

That bundle has to go to your outdoor A/C unit then, unless it gets spliced somewhere along the way. There’s one way to check which of the Y wires is the outside unit without opening the outside unit, and that is to disconnect any thermostat you have connected and take both Y wires off the furnace board and carefully touch one of them to R. Whichever one sparks or turns on your outdoor AC is the one that feeds the outdoor unit, the other wire should be just for the thermostat. However, you should make sure you have a spare 5amp automotive blade fuse, because this can sometimes pop the fuse.

Ok I’ll give that a try, but first you were right. There is a splice I found where the bundle gets separated into 3 red and white bundles. Here are the splices:
Red and white to red and white.
Blue and orange to red and white.
Yellow and green to red and white.
This makes sense as at the thermostat I have 2 sets of red and white.

Is this helpful or should I go with the approach of touching the wires to R?

Your outdoor unit uses Blue and orange, so leave those wires where they are.
You want to connect the Red, yellow, white, and green wires from your furnace to your adapter, and attach the leads from the adapter to your furnace terminals as follows: C wire to the terminal with the blue wire. G wire switches places with the green wire. R switches places with the red wire, W switches places with the white wire. Y switches places with the yellow wire and the orange wire stays in that terminal with the Y wire.

That did it!

Thanks a lot for all of your help. I appreciate it.

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