car says left rear door is ajar and mirror lights and dome lights wont shut off because of this ,have checked door few times and is shut all way and no obstructions in way
left rear door on 2007 Lincoln MKZ
I was having this same problem with my 2008 Lincoln MKZ. I've had it in the shop twice now and the technician hasn't been able to recreate it so he wasn't able fix it. At first (several months ago) all the interior lights would flicker on and off while I was driving. Last week, however, they all came on at night, which was very distracting having all the lights on while I was driving, and would not go off at all and the battery was dead the next morning. Turns out The keyless entry number pad on the driver door (where you enter a code to unlock it) has an issue with moisture developing in it which causes the computer to think the door is ajar therby causing the interior lights to come on. They replaced my keyless entry pad and used an new and improved seal around it to prevent another moisture accumulation. Hope this helps alleviate for someone else the months of frustration I dealt with from this problem.
At times, the door ajar switch can be faulty, or can just stick. This is located in the door latch itself. The only thing you can do besides replace the switch or check the wiring is to spray some lubricant into the door latch area, and then open and close the door several times to work in the lube. It is possible the switch will again start working. If not, then you must circuit test to make sure there is no short, and then condemn the switch itself if all else checks ok.