by lotusflasherman » Mon 19.12.2016, 18:23
Worth noting that those interior lights are permanently 'live' at +12V and all the switching is done by providing a -ve earth return, or not. Therefore faults or stray earth connections 'downstream' from the lights will keep them on.
(The mirror light supply also provides a very convenient source of 12V for screen mounted items like SatNav, Snooper or Dashcam, but remember it doesn't go off with the ignition.)
Interior Lights can be turned on by individual switches on the mirror, or by pulling out the main light switch and will go off immediately when returned. Opening either doors closes a microswitch, that is screwed on the door latch, and provides an earth to put the lights on and when the door is closed the Interior Lamp Delay Module keeps them on for a further 3 seconds (on my late SE) but they'll go off immediately the engine is started in that time.
I think the most likely part to fail first is going to be a micro switch on the door lock and I'd be checking the drivers side, as it gets much more use, before I checked the passenger side. Tom has already had a problem with one. You'll have to remove the door panel to inspect and the microswitch has a 2 wire connector that you can pull out to break the earth connection. If I needed a new microswitch I'd be looking at RS Components online catalogue.
There are also Central Door Locking microswitches and Door Ajar microswitches in each door mechanism so I'd avoid unplugging the whole door harness as all these will stop working too. Removing Fuse A14, as you've done, is the best way to avoid a flat battery as it only feeds the Interior Lights so you haven't affected anything else.
Phil
Leave me alone, I think I know what I'm doing.
Cars: Subaru Forester 2.5XTN, Eclat Riviera, brace of Pacific Blue SE's, Collapso SE, Elan+2S.... and now an Evora