Open the doors one at a time....
Which one when opened DOES NOT display on the DIC?

they all display, i checked today :?

im really betting its your trunk latch monitor... in the trunk lid, remove the carpet. by the latch there is a electrical connector. unplug it and close the trunk then rearm the system, see if the light goes off....

Do any of the doors... delay displaying on the DIC when opening?
.... and check your trunk latch

the DIC doesnt use the plugers in the door jambs.... the security system uses the plugers. you might want you remove each pluger and check to make sure there is TWO wires plugging into the plugers. one is the ground to the lighting system, the other is the signal to the alarm.

I know the DIC doesn't use the plungers... The plungers are only for the lights.
Security uses the latch as does the DIC doesn't it?

If a plunger was busted and the security light was on, wouldn't the dome lights be on too?

Depends how it busted...freqently plungers give up and stick closed

security system uses the pluggers, but if one of the security wires was busted off the pluger, and it wasnt grouned when the pluger was "in" the system would not know the door is closed.

directly from my 91 FSM:

SECURITY LIGHT GLOWS, BUT SYSTEM WILL NOT ARM

check lock cylinder switchs for signs of tampering.
Check switches for loosesness. Check for frayed or pinched wires to clyinder or jamb switches. CHeck jamb switchs for proper adjustment and clean connection. If all circuits are okay, Replace Controller and relay.

if you need wiring diagrams of the theft system and lock system. let me know i have them on CD