send 12V+ when continuity to ground is broken

I went temporarily brain dead. What I'm trying to do is send 12 volts thru a wire when continuity to a ground is broken, Could someone point me to a diagram or help me pin this out? 

I am looking to do something similar.  I have a trunk release button that I want to be disabled when a (-) lead from my alarm grounds.  I had 86 and 30 on constant 12v+, 85 to my alarm ground when armed wire, and 87a to the trunk switch.  I thought it worked, I could pop my trunk and when I armed the alarm it broke the circuit, but when I disarm my alarm and 85 is ungrounded for whatever reason the coil is not interrupted and continues to keep 30 connected to 87 (which is nothing).  If I pull the relay it will reset and I can use the switch again, how do you make the coil at rest without a switched +12v?

Here's what you can do - assuming it's a positive switched trunk release. 85 to the ground-when-armed, 86 and 87a to the switch side of the trunk relase solenoid wire, and 30 to the solenoid side of that wire. What happens then is whenever the trunk release button is pushed with the alarm disarmed, it works as normal. With the alarm armed, the shortest path to ground is across the coil of the relay, therefore when you press the button it activates the relay and cuts off power from the solenoid.