i live on a small budget and finally aquired an older goodman furnace (gmpn080-4) and ac which were in very good condition out of a friends place and had only been used for 2-3 yrs. even the condenser outside was kept covered and secured when not in use . that said the units were in full working order together . they have been installed at my place all duct,furnace,a-coil,condenser (and charged) ,gas and main electric work is done . but now i need some help on how to reconnect the low voltage wires .under normal circumstances i think i would have no problem but this furnace model has no Y terminal !!! i only have 3 wires from the board W G R i bought a basic thermostat for heat/cool ran a 5 wire of it and connected it at the thermostat as required also ran wire from condenser to furnace (airhandler). now i look at 5 wires from thermostat and the yellow and red from the condenser as well as the 3 wires red ,green and white from the furnace .missed the chance to be there during dismantling and i do not want to make a mistake and ruin what i have . where do they go ??? ( i do not want to break the rules here by posting a link but pictures often tell more then words .there is an ebay listing that shows my exact board under the tittle : OEM Goodman Janitrol Furnace Control Circuit Board Panel B1809913S to see what i have ) i used to have grey hair but it turned white from googling this for days is there a way you could steer me to a wiring schematic that shows where i need to connect (assuming doubling up )the wires from the condenser to the board . the heat side i think i understand where to go. just not were i need to double the connection for the 2 wires from the condenser any help be truly appreciated and thanks in advance !!!

  • Please post pictures! If you can't upload them using the built-in function, upload them to imgur instead and put a link in the comments Apr 26, 2017 at 1:03

1 Answer 1


The furnace doesn't need a Y terminal, and in a lot of cases when it does have one, it's not connected to anything in the furnace. Connect the wires from the thermostat as follows:

  • Red connects to R in furnace and R on thermostat.
  • White connects to W in furnace and W on thermostat.
  • Green connects to G in furnace and G on thermostat.
  • Yellow connects to the Red wire to the condensing unit.
  • White wire from condensing unit connects to 24V common terminal of the transformer.

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  • The 24V common terminal of the transformer should be grounded to the chassis, as well as connected to PIN 6 of the Molex connector on the board.

  • *The "hot" 24V terminal of the transformer should be connected to PIN 3 of the Molex connector on the board.

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