How To: Reset Factory Alarm
There's some 1st gens out there without factory enabled alarms that are somehow turned on. If the BCM memory has it on, then the PCM also has it on. Replacing the BCM only will still have it on under influence of the PCM. Replacing both may still have it on.
Here's a cheap ($5) and easy fix.
Install a manual alarm reset switch, in 30-45 minutes.
1. Remove the bcm from behind the passenger kick panel by removing 1 Phillips screw, lower it to unplug the 2 or 3(premium) connectors.
2. Place on table, undo the 4 Torx cover screws.
3. Look at the BLACK connector and locate pin 3. That's "lock disarm". Carefully solder a 4' length of #18 or 20 ga wire to it inside the case. (Or splice into the harness wire, 22ga LG/OR)
4. Look at the BONE connector and locate pin 21. That's "body ground". Solder a wire to it inside the case. (Or, the harness wire is 20ga Blk)
5. Extend the wires out of the case through a cooling slot.
6. Plug the 2 or 3 connectors in and install bcm in kick panel.
7. Route 2 wires to a hidden but convenient spot under dash and connect a small momentary on switch. If the alarm is tripped for any reason, pressing this switch will now reset it. It takes the place of a factory door cylinder switch.
8. For an "alarm on" indicator, also solder a wire to the BLACK connector pin 10. (22ga Blk/OR) That's "VTA set lamp". Extend this wire out to a desired location and connect a 12v lamp or LED, ground the other side to the BONE pin 21 wire of the switch.