I want to wire up my alarm to go off if the hatch opens. I was going to hook it up to the black/orange wire that goes into the light back there, but when I was testing it, I found something curious....

The wire is grounded when the hatch is open, but now while it is closing. The part I find confusing is when the hatch is fully closed, the wire is grounded again. So this would set the alarm off then would it not?

Does anyone know if the is the correct wire to use? If not, which one should I be using? The input for the alarm can be + or -.

 

the pin should only be grounded when the hatch is open. If it's grounded with the hatch closed, something isn't right. Either the switch is grounding out by touching something it's not supposed to, or you've got some sort of funky wiring issue.