Re: BA Falcon - door open indicator stays on.
My answer: It was the main unit under the dash that needed replacing. It cost $1000 at a "cheap" auto electrician (NZ) but he had to import the unit from Aus so for you Ozzies it might be cheaper. He examined all the individual door units before taking the dash apart to get to the main unit. Had to be done as I couldn't lock the car, and when it auto unlocked all the interior lights would come on draining the battery. He also broke the centre top vent when accessing the unit so careful when doing DIY as they must get brittle from the sun?
Now I have the left rear door that doesn't lock and it will cost $300 to fix but I can't be arsed - the other doors lock so I'll just chance it and not leave anything valuable in the car. Might try DIY as suggested above, and as said, there is a whirring noise from that door when I lock the car.