Noticed the interior lights had stopped working a few weeks ago. Spent some time and neck ache checking the wiring from the BCU, decided the BCU was probably at fault and not switching to ground.

Decided to do a courtesy door switch installation .......... was not to concerned about lights coming on from the key fob.
Purchased two door switches from EB/Y, about £4 drilled holes in the front door pillars and fitted the switches, removed the windscreen side trims and fed wires up to the light switch, attached the two wires to the center bar to the right of the switch base, this is the ground point if the system was working properly.
I now have all three interior lights working as they are looped together, triggering from both front doors with no dimming of course. Took about one hour.

Thought I would play a bit more! I had some larger LED panel bulbs from a Saab I was reconditioning so I adapted them and installed, I then added some capacitors in Parallel to the LED bulbs, I used 15v 4000uf front and back, voltage does not matter too much but the uf will determine how long the LED is on after it is powered off, mine is about 5 secs, just enough to see whilst starting the engine.
Take care to get your poss and negs correct, I did mine on a bench before installing.

If anyone is interested I can add a bit more information.

Frank

This sounds very interesting.
I too have interior lights that will only come on if I switch them on at the light.
Not too bothered about any delay!

Hi, i respect your work albeit you should have asked before fitting additional switches as there is a more simpler way to bypass the BCU if that's what you want(not my way of fixing things)... the switches and wiring are already there all is needed is to splice into two door switch inputs to the BCU(one is from the driver's all the rest of them are on a single wire) and run a wire from there to a point where it goes to the lamps and they would come on for any door not just for the two fronts. In most cases this interior light problem is caused by corrosion in a header cos if it was the BCU other thigs would go wrong as well