pd-175 (beating a dead horse)

lies lies...... why is it i'm the only one who seems to have figured out that all you need to do is hook the wire from the alarm that is supposed to go to the oil pressure sensor, instead to the alternator field wire.  on really old cars, the oil sensor would work fine - here's how the alarm determines if the engine is running: 

sensor wire reading low: engine not running (i.e. no oil pressure)

sensor wire reading high: engine running (oil pressure brings the sensor up off the ground, and so the wire reads high from the voltage either across the light bulb, or the oil pressure guage)

the solution is simple and actually works better than using the oil pressure sensor - especially on late model fords that the sensor is of a totally different type -- connect that wire to the field wire on the alternator instead.... engine not running, field wire reads low (i.e. alternator light on dash is lit) -- once engine starts, field wire reads high (and makes the light go out).  i don't know why the alarm manufacturer didn't figure out that, but they should have.  so should anyone else with basic vehicle electrical skills.