I don't usually like to awaken old threads like this, but in this case I'm having the EXACT same issue and what seems to have been the "concensus" DOES NOT WORK.
If I hook the buzzer plus to +12 and the buzzer - to the Yellow, it starts buzzing.
I verified... when the GPS
goes into an Alarm
state, the Yellow pulses 1V. I verified this not only with a meter but if I hook a low voltage buzzer (not very loud) between the yellow and ground.... it works properly... just quiet.
What I apparently need is a 1 Volt relay that can handle 12 volts across the switch.
I just got off the phone
and they are sending me an actual schematic to wire the relay. They say a standard 12V relay should work...
Much like the original poster, I have been all over the web on this. It doesn't help that I actually have an electronics
background... went to school
for it and everything. It isn't rocket science. Apply voltage across coil.... causes switch to trip...
Sheesh.... It should not be this tough.