How to turn off alarm 1994 Pontiac Grand Am SE while changing battery?

A 1994 Pontiac Grand Am SE doesn't have a memory-backed alarm system in the way that modern cars do. The alarm is likely a standard aftermarket add-on. Therefore, disconnecting the battery will *not* set off the alarm, and you don't need any special procedure to disable it while changing the battery.

Just disconnect the negative (-) terminal first, then the positive (+) terminal. Replace the battery, reconnect the positive (+) terminal first, then the negative (-) terminal. The alarm should not be affected.

If, after reconnecting the battery, the alarm *does* sound, it's likely due to a problem with the alarm system itself, a faulty connection, or a low battery in the alarm's backup system (if it has one). Consult your alarm system's documentation (if you have it) or seek help from a qualified auto electrician or alarm installer.