I have a Goodman Furnace and central air but can not figure out wiring to the thermostat.


furnace = red green white blue

ac= black white

thermostat= r rc g w y


Which wires go were?

If it was me, I would try:

Furnace Red Green White Blue
to to to to
Thermostat R G W Y

There is a good AC guy hope will save me before you blow it up(Just kidding,worse you could probably do is try to heat and cool at the same time.
Red is common
green is fan
white is heat
I believe yellow or blue used for cool.
To get cold, Red touches Green for fan to run and yellow? for compressor contactor.

If it is GMP or GMT series the blue wire is your common
Attatch
R to R
G to G
Y to Y
W to W
Condenser Wire one side to Y
THE OTHER TO BLUE

http://www.askmehelpdesk.com/heating-air-conditioning/heating-cooling-maintenance-repair-troubleshooting-frequently-asked-questions-58313.html#post268211

Excellent info from NorthernHeat, Pop bear may be right.
To be sure, Pull cover off, and verify connections, wire colors. Schematic may be inside panel.