[Starglow]

I'm not sure why you tempted fate by putting the old switch back in again after the problem seemd to have been fixed unless I'm reading your post wrong. I'd disconnect the battery for at least 30-minutes. Put the new switch back in and then reconnect the battery. If the car won't start, do the relearn procedure again. If still no start, check the electrical connections on the BCM for corrosion and also verify fuel pressure is present at the fuel rail with the key on.

When doing the relearn procedure after the car won't start, do not turn off the key after trying to start the engine because the relearn may fail. Also make sure all doors are closed and all electrical devices are turned off. I learned this from Mike (Milzymotorsports) and have experienced it on my own GA which is the same car as Alero.