Just want to make sure I have this correct: Have M1MB 070a BW heat/ac unit w/ a 710152B control board and a Coleman outside condensing unit. -Have a four wire thermostat. R,Y,G,W -Have 2 wires coming in from an outside condensing unit. R,W -Have four wires to connect to from control board R,G,W,Grey (marked "C" on control board)

I've connected R to R, G to G, W to W, Y to the white terminal going to condenser unit, and red terminal connected to outside condenser unit to Grey (marked "C" on control board)

do have pics of rat nest if needed

  • Is there a test procedure that you can follow to make sure all functions work properly?
    – Freiheit
    Commented Jan 9, 2015 at 16:45

1 Answer 1


If there's a Y terminal on the furnace, you should connect the Y wire from the furnace and one of the wires from the condensing unit to it.

I typically connect the red wire from the condensing unit to Y, and the white to C. Not that it really matters, that's just how I do it.

Other than that, it sounds good.


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