I'm thinking of getting an alarm and doing the install myself. I need to know if the door locking is postive or negative output.

 

no one knows?

After some diggin in the service manual, found out that our security/keyless system is tied to a BCM that controls the doors, horns, lights, etc.. , but can't seem to find if the doors locking is set off by a negative pulse or postive.
Reading this, raised another question. Will disconnecting the BCM affect the car's ECU in anyway?

 

The Z has negative door lock, and negative double pulse unlock. You do not need to disconnect the BCM to install a alarm.

 

Thanks for the reply. But if I don't disconnect, won't the stock alarm still work?

 

Then you would have 2 alarms. Whats the harm in that. The only thing special you would have to do is if you plan on doing remote start you need to hook up the "factory disarm" wire from your AM alarm to the disarm wire on the OEM alarm. That way it want set off the factory alarm when you remote start.

 

well, don't want to carry two keyfobs. Thats why I want to know if the factory one would arm once new one is installed. not going to use the remote start, it only works for auto not manual.

 

Silly rabbit. You want have to carry two remotes. Your OEM alarm will arm, and disarm off the lock, and unlock wires of you AM alarm.