I need help getting my goodman furnace working, I've changed the igniter and the pressure switch and it still isn't working. The light keeps blinking and it says on the door that it's a 115v reverse polarity, does anybody know what that means?

Odds are you are going to need a new control board. Reverse polarity means the nutral and the power are hooked to to wrong wires. But inless you have change some wiring lately this can not be the case, thus probably your control board is going bad.

If I were in your place I would unplug the furnace and go into the box where the power cord enters the furnace. I would disconnect the Black and white wires, All The Time Remembering Which Wires They Were Connected To. Now I should connect them back just the opposite from how they were.

If this does not do the job I would then switch the wires where you connected the new pressure switch.

Let me know what happens.

Thanks guys, I'll let you know what happens