cobalt trunk pin

Hi, My friend has an 05 cobalt that uses negative door triggers but a positive trunk trigger. Is this possible? We hooked up the door triggers and they work fine but when measuring the trunk pin located in the BCM c1 pin 55 ORANGE / black wire, it is 0volts when closed and 12volts when opened. Is there a way to reverse this? I dont think his alarm as the function to change just the trunk pin to a positive trigger. If he does this, all the triggers will become positive. Thank you.

Keep testing ORANGE / black wires in connector c1 at the bcm. Its a negative trigger for the cobalt trunk pin.

Should be in the same connector as the door pins,

where do you have your multimeter connected?  black to ground and red to the ORANGE / black wire? or do you have red to 12v and black to the ORANGE / black wire.  If used the first setup then it is a (+) trigger-odd-, but if you did it the other way then it was (-), either way you can convert that positive signal to a negative signal.  With a relay you should connect the ORANGE / black wire to 85, (-) to 30 and 86, and 87 to the trunk trigger of the alarm.

Well thats the importance of checking all your wires with a meter.  You were lucky that it wasn't an alarm wire that was giving an output(triggers are inputs).  Good job checking with a dmm and not just connecting and seeing if it worked. Now, with the odd part,  you shouldn't worry, its just how things work sometimes. Again, good job testing.