neg trigger to disable 12v

I have a negative output that I need to use to disable my electronic boost controller. my boost controller turns on with the ignition normally. I only want it to be disabled when the negative output is enabled ,and then I want the boost controller to turn back on when the negative trigger is not present. What would be the easiest way to have the negative trigger disable my boost controller which has just power and ground... example just break the 12 power going to it  similiar to a starter relay setup?

Im not 100% sure if it would work right this way or if i would have to wire it to where my ignition needs to be turned off and back on to reset the relay any help would be appericiated

take an automotive relay and wire pin 85 to +12v with some fuse protection (1A at the most)

wire pin 86 of the relay to your negative signal.

wire pin 30 to the +12 supply side comming from the ignition that is currently going to the boost controller.

wire pin 85 to the boost controller's power input.

the negative output is coming from my wideband setup it is a constant negative pulse when the car is to lean and at a certain boost level it sends out the negative trigger.  That way it will flip my boost controller off more so to protect the engine. I think ur first idea should work just fine when the negative trigger is active it will break the power to the boost controller until the trigger goes away .

The boost controller will turn back on, it isnt a latching relay..

What happens is when the negative trigger is on it completes the circuit for the coil in the relay which energizes it.

Once energized it opens the contact between power and the boost controller, effectively turning it off.

As soon as the negative trigger goes away the circuit on the relay coil is open and the contacts close again which will allow power to flow to the boost controller again.

Just curious, the circuit you are using to detect a lean condition does it use some kind of hysteriesis or debouncing?  if not it has the potential of rapidly turn the boost controller off and on.