disarm and arm both lock doors

I am connecting the arm and disarm feature from a Code Start alarm on a 95 integra.  when I hook the negative pulse wires up separately (-lock and not -unlock or -unlock and not -lock) it works the way it should.  when i  hook the lock wire up and the unlock wire up at the same time, they both lock the doors.  The arm and disarm are hooked up to two separate wires in the drivers footwell and my metering shows them to be the correct wires.  I am lost on why they act differently when both are connected.

Have U metered the Factory wiresto make sure?

the Ground Pulse from your Code Start may not be strong enough to do both functions & U may need to use 2 Relays for Ground Pulse