factory alarm shutdown wire (keyless install)
 

putting in a keyless entry and remote start. i know the lock tumbler send a - pulse to the oem alarm when the key is inserted and turned (thus disabling the alarm). the keyless system i have has a wire "factory alarm shut down", which sends a brief - pulse. would i just cut the wire going to the lock tumbler or just "T" into it so that when i lock and unlock the car with the remote, it will enable and disable the alarm?
sounds simple enough to me, just making sure my "thinking" is correct.

does the factory system arm with the same - trigger.. you would have to find out how that works, is it - to arm if disarmed and - to disarm if armed, if so then you also have to verify that the system you are installing is the same, if you have seperate wires on the aftermarket system that arm / disarm factory alarm then you should probably get some diodes so that the current can only flow FROM the aftermarket system so that it doesn't get stuck in a loop of arming and disarming ie it sends the neg sig out and reads it and sends it out the other wire...

but to T the wire in is the correct way to do it, in case you lose your keyfob or the battery dies you can still get in...

You will just need to tap the unlock signal or pulse when disarm wire from your new alarm into the dark green with the black stripe wire (driver kick panel) and add a diode N4001 in between.

This will retain the factory stock alarm to work in parallel with your new alarm.

its not a new alarm, its just keyless and remote start. i wish to retain the factory alarm. and why do i need a diode inbetween the wires?

yea, keyless entry will be wired up the same way

I posted in a different thread, here's my write-up with diagrams:

https://www.rx7club.com/interior-ext.../#post12133384