Actually it’s my father’s 1995 Nissan 200SX SE-R with factory type I anti theft. One morning the battery was dead so he hooked up the charger which made the horn sound and lights blink. He disconnected the wire at the ‘+’ battery terminal and successfully charged the battery. When he reconnected the ‘+’ cable the horn sounded and the lights blinked. Then he removed the anti theft fuse. Now the ‘+’ cable can be connected to the battery without the alarms going off, however, the car will not start (does not even crank). We suspect that there is a short somewhere in the anti theft system. It’s an old car and he does not care if the anti theft works but he would like the car to start. He is going blind, but together he and I are competent do it yourself-ers. Any advice? Thanks, George K.
Put the fuse back in. When the lights blink, lock and unlock both doors with the key. This will usually de-activate the alarm. If it does not, put the key in the ignition, and try to start it. See if that will de-activate.
Normally alarm systems have to reset when the power is removed. This is usually done by pressing the unlock button of the keyfob or reset button inside the car, if it has one.
If there is a current drain then this link may help you find it.