How to turn off factory security light on my 1991 nissan 300zx?

Is it always blinking, or on solid?

always blinking except when car is on.

could be your hood sensor. i have 1986 and hood sensor is gone so light blinks all the time. def killin your battery

Yea, if its blinking that means the time control unit thinks that something is open. IE: hood, door, hatch. unplug the hood switch and see if the system arms. When everything is functioning properly you shoul lock the door, and the light goes from blinking to solid for 10 seconds then turns off.

HA HA HA! I couldn't figure this out either... my solution was to remove all of the lights inside. I believe it was a grounding issue... like a short in the wiring somewhere. I've actually just sold my baby, so I suppose now its up to the new owners to figure that one out too.

Mine does the same thing and has done it for years. It has never run the battery down even if it sits for a long time withou running.