In response to the double lock feature on E36 cars, the double lock feature is enabled by momentarily applying 12v+ to both the lock and unlock wires at the same time. My own alarm is hooked up this way and I wouldn't do it any other way. Why waste good engineering? This is how I did it using a clifford alarm; set the alarm to give a momentary 12v+ pulse on both lock and unlock, hook the unlock wire to the unlock lead coming from the alarm also hook a diode to this lead with the line facing the towards this lead, now hook the alarm lock lead to the lock wire on the car and hook the free end of the diode to this lead also. When you set the alarm the diode allows the 12v+ to flow to both lock and unlock wires at the same time while isolating the wires when the unlock wire alone is activated. Viola a proper alarm installation, that takes advantage of double locking.

RL 95 M3