I've just installed a roof mount screen in an AU Falcon, but when the doors are closed the interior light stays on. The screen's light has a constant power, earth and a negative trigger wire, I know the problem is coming from the car because the trigger wire still see an earth when the doors are closed but I dont know how to fix it. Can anyone please help!

that car has a body control module in it. what EXACTLY did you tie into?

I patched into the wires that go to the interior light

ok that circuit is timed. after 5 min on being on it will turn off grounding the switch side. my suggestion to cure this is to take the light wireoff the display to teh drivers door switch and put a diode on it to isolate the screen from the car. take power from under the dash. there is a 4pin phone plug underneath the dash left of the steering column. use the yellow and black wires for power.

that will fix your problem.