Red led lights indicate pressure switch is open, where is the pressure switch or valve?

It is a small black switch with to wires on it and a air tube.

http://www.mobilehomerepair.com/media/img/nordyne/632409.jpg

Are you sure you vent motor is running?

Thank you for responding.
Vent motor? That's what it's called?LOL

After looking and reading all information on-line. I went back to the unit and removed the gray tubing blew into in. tried to restart he unit. No blinking light, and the unit fired right up. This is a new unit, it was free and we replaced our 20 year old coleman furnace with it. So no instructional manuel no warranties. Was working just fine. I live in N Arizona we have had a lot of winds and dust. And I wonder if it was just clogged?

Thank you
For responding.

Carmen

Glad you got it running. Dust mositure, or anything can cause the pressure switch to stick. Have a good day!

Well it's not working again, how hard is it to replace that part and where do I get it?

As I was saying it may not be a problem with the pressure switch. It could be your venter motor. Or you chimney. Check you cap on the roof and make sure it is clear. Pressure switches very rairly go bad.

My was turned off, at the time I did not worry too much because I was running the air condition. The air condition works, but now I need the furnace. When I turn the switch to heat nothing happen so I looked at the light. It was blinking twice. What can I do so I don't have to call any body. Please help. Thank you for your time.

Check to make sure the combustion blower is running. This will the first thing that will start when calling for heat.

Should look something like this.