when you open the door and close it - what activates the interior light, old days doors had poppers, none of these now, so where and what does this ?

I believe it's controlled by the GEM and the switch itself may be somehow integrated with the door latch. Not that that means a lot to me.

Is there a problem with yours? I never actually use the light tbh

Hi Jimmy, a while back my dash warning light was coming on stating driver side door open, when in fact it was closed, as it was doing to too many times I ended up going to ford and while I was there he undid the connector that goes from the car to the door (the big plastic tube connector) and messed about with it showing me the pins can get worn/bent etc, I asked for a new one which cost a lot. I'm not that convinced anything was replaced as that connector looks just like the old one ? unless it's the wires within it.
Anyway, after that it did come on now and then but mostly okay.
Lately the warning light has been coming on again, I have notice that if I lightly close the door then the warning light comes on. If I close the door with a decent bit of thump then the warning does not come on.
So, I've ensured the connector is tight (they do come loose, just hand tighten it until it locks solid), sprayed WD40 on the door latch and catch and inside the door lock as well - hence I'm trying to pin down the activator part whatever that is, as you say perhaps the latch earths it ?

Does pushing the door latch in to lock it from inside the car make a difference by any chance?

thinking similar, I'll close the door fully, start up, check no warning lights on, then give the whole door a shoulder shove and I'll try the door lock as you say see if light come on, good thinking.

okay, gave door a hard shove, all fine, tried the interior door handle and as soon as you start to pull the handle the dash warning light comes on. So, the warning is linked to opening and closing the door and must be a sensor attached to the door locking mechanism, I doubt I needed that loom replacing although at the time the light was coming on a lot and after hardly at all until now. Not much I can do, I'll try and spray some WD40 in as much of the door handle inside and out and inside the door lock/clamp areas as much as I can.

Yeah, sounds related to the handle or handle mechanism in that case, or the sensor is being very sensitive to movement. What I was trying to say is, when the warning is on can you still lock the door from the inside to turn the warning off (or does it not let you because it thinks the door is open)? If it does, that's what I'd do to remedy it, not ideal but if it gets rid of annoying messages for the time being it's one idea.

I did try that today, warning light was on whilst driving off, I pushed the lever inwards and I heard the locking mechanism work, but the lever did not remain in the locked position, it returned to normal, so not sure from the outside that it was locked (prob need window down and reach and try it) the warning light stayed on and of course the interior light comes on and stays on as it thinks door is open. I'll try it again though, I just opended the door at the lights and slammed it hard shut and warning light goes off.