[nvme334]

I have a Trane unit on the outside of my home and a Miller in the inside. The gentleman told me that the wires from the outside condenser are not matching up with the inside air handle. So the reversal value is not cooling only heating up. Can someone please help me?

[Stratmando]

Get someone else.
The Outside Compressor unit usually only uses 2 conductors to control the Compressor Contactor.
The Heat wires don' even go outside, only from thermostat to Air Handler.
The Thermostat will usually have at least 4 wires:
1)24 Volts(Red)
2)Wire for Blower(Green?)
3)Wire for Heat Strip(White?)
4)Wire for Compressor(Blue or Yellow?).
Colors may be different than above, check connections in air handler to verify what is what.
Must be a splice somewhere, if colors are different at both ends, Need to tone out, or identify each conductor for continuity and no connection between the 2.
Thermostat could be wired wrong.

[Grady White]

Is the outdoor unit a heat pump?