I found this decsription for 5 blinking lights. You may have a problem with the gas valve. Find a qualified tech who knows who to service Amana furnaces.

Flame Sensed with No Call for Heat.If the controlsenses a flame when the gas valve is de-energized, it will run the air circulation blower and the induced draftblower continuously with no further furnace operation.The diagnostic flash code for this is afive flashes. Theprobable causes are either a short to ground in flamesense circuit, miswiring, lingering burner flame or a slowclosing gas valve.

Here is a link that might be useful: Amana Furnace Service Instructions

My question is why would a tech replace a pressure switch when blower motor runs continuously? If a pressure switch is bad the blower will not cycle at all. If it is tripping on high limit then the blower will run. Also I doubt a loose will will cause blower to run continuously either. I would call another company and cut your losses now.

Thanks for the info............ If I get the same problem again I'll call someone else. It seems to be working ok for now.

Thanks,
Scott