My goodman pgb03075-1a stop blowing air. Took it apart and saw no flame when auto ignition fired 3 tries. It shuts off then led light constantly flashes. Not one of issues listed. Called goodman co. They said it was reverse polarity how do I fix?

Redial that number, they should know.
You need to know reverse polarity of what.
I would bet a loose/bad connection.

They would not say, person responded that they don't have technical help, but to call for service.. punks!! But just remember something about 24 volt/??

I'm thinking of something in the circuit board because, pretended to call one of the gas servicemen. He kind of looked over it and first suggested the gas regulator because it had no flame when ignited. Then he told me that his brother had a situation where the led light flash none-stop, so he said change circuit board??

I found this, but don't believe it is 120 Volts? And don't believe you reversed the 120 volt wires:

On my central air inside - FixYa (http://www.fixya.com/support/t9044998-central_air_inside)

Sounds good? It could be last resort. But now after changing the circuit board, there were four flashes, which means the limit switch is open. I'll try to replace it, better work. Thanks for the update!

Oh, and another thing why would unit work all these years without problem, then all of sudden it's reversed?? Confused!!

Didn't touch those wires at all!!

I didn't think you messed with the wires. I would jump out the limit switch at the terminals and see if the trouble clears.

This is all new to me, so how would you go about doing(jump out of the limit switch) it? Just want to know? But I did ordered a new one because the led light flashing indicated it. It was cheap 18 bucks. It should come tomorrow. Thanks I'll update bro!

A limit switch is usually 2 wires and is normally open, or normally closed. You can make or break a connection to simulate.

OK thanks, have to wait till Monday for switch to arrive. But if I have time this weekend I will try... get back to you thanks again!