I have an error code that says the aux spill swich is open, But I think it is just going bad because it works sometimes and may be getting ready to go bad. Where to find an aux spill switch for york diamond 80 furnace?

Never heard of a aux spill switch? Is your unit in the attic?

How many flashs is the fault code?

Four times

Not in the attic but in the wash room next to water heater

If it is in the wash room odds are you need to clean the flame sensor

Laundry deturgant cause a biuld up on it and will not let the flame stay on properly

Four flashs is usually limit switch on york furnaces. Not sure why is says aux spill!!

I have no knowledge on a furnace I found this info on line and got the error codes, where and how do I clean a flame sensor

OK no problem, I will help you threw this.
First take the top door off your unit

Then locate the burners, on one side will be the ignitor, usually the right. And on the other side will be the flame rod.

Done

http://www.mobilehomerepair.com/medi...-30788-700.jpg

Rub this with a piece of sand paper or steel wool

Have you ever watched the unit to see exactly what is going wrong on it?

Also your fault codes should be on the back of one of the doors, or in your owners manual

THANKS for the info I will try it and reply later!

OK let me know, hope it works for you

Yes, If I turn the unit off and back on after I take the cover off it seem to for fine over night but when I get home in the evening it's back to the same thing. That which is I turn the thermostat up it kicks on and off after a quick cycle and goes off until I take the cover off and restart it again

How is your furnace filter?