Bizaar '96 PassLock behavior... HELP!

This is from my son:
I own a 1996 Chevrolet Cavalier. Recently, it has not been starting because the passlock system is on the fritz and it thinks I'm stealing it. When
trying to start it, the "Antitheft Device" light comes on, then I turn the key, and it stays on rather than starting the car and turning off as it should. In an attempt to fix it, I removed the ignition cylinder and took out the module, looking for a physical switch and finding none, so thought maybe it was a magnetic switch. Holding a magnet to it and turning it over, I got it to start and stall. After dragging it home I went to a junk yard and pulled a new ignition cylinder and instrument cluster, hoping that switching out the system altogether would work, but to no avail. An employee from Best Buy told me that the passlock system was stuck in "on mode" and that this could be fixed by the following procedure: 1) open the drive side door and leave it open, 2) disconnected the negative battery connection and let it sit for 10 minutes, 3) reconnect the battery and put the key into run position, but do not crank it. Wait 15 minutes, 4) turn the key to the off position and then turn the car over. I did this and it started but then after 15 minutes or so it went back to not working. Recently is the strangest of all however. The engine cooling fan now comes on after putting the key into run position, at which point I can start the vehicle. However, it seems only to start WHILE the fan is running, and no other time. In the last two days the fan has not been coming on though, and I cannot start it. As I have no other means of transportation I was hoping someone would have some words of advice for me. I'm a junior in high school and can't afford to take it to a shop. (I only gave $800 for it in the first place.) I would be so grateful for any pointers to a solution. Thanks!
Alas, I really am unable to do anything for him either. Would much appreciate some idea of what's going on here. Bruce

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