Marc and I still can't figure out why the dome lights are on, even when the delay timer is disconnected. Could it be that the drivers door switch is open? When I took it out it only had one lead coming from it; the wiring diagram shows two leads. Could one be disconnected (the ground?) and that is why the dome lights stay on???
I believe the plunger-type door switch (near the hinge) is only for the key warning. My understanding is that the switches for the ARC and dome light are in the latch mechanism inside the door. But I've never mucked about with it myself.
If they are like the interior lights in a Spider or GTV6 there is a switch to choose from automatic (on/off with door), always on or always off. In the Spider's footwell lights the lens acts as the switch. In the GTV6 & the Spider's rear view mirror light there is an actual switch button.
Have you got a sunroof (so two interior lights either side of it) or no sunroof (one big light in the middle)?
If you've got the two lights, the lens unit is a rocker switch which allows you to switch the interior lights on independently of whether the doors are open or not. It may be that one of these is switched in the on position or just slightly "rocked". Mine was like this and it drove me insane for weeks until I figured it out.
If you've got the central light, the on-off is controlled by a switch up by the window switches/interior mirror. Is this switched on?
If it's not either of these then there's a wiring hiccup in the door switches which are in the door catches themselves. A fault here would normally also make the "door open" warning on the ARC light though.