The fuse had blown on my interior lights. After changing the fuse everything seemed to be working ok, however, once on the road, after about a mile all the interior lights came on. Checked all the doors were all properly closed but lights still on. Tried switching lights off and this is what i found -
*The back of the two lights in the cab stays on regardless of the switch positions.
*The front of the lights goes out when front switch is in middle position.
*The front light also goes out when front switch is in forward position whilst back switch is in middle or rear positions.
Any ideas?

Gareth, October 2009

Thanks for the excellent advice. Seemed to have solved the problem. I had changed a bulb in one of the back light fittings a while back and couldn't have replaced the housing back into the van properly possibly causing the metal contacts to touch the van ceiling. Thanks again.

Gareth, October 2009

one of the door switches will be faulty end need replacing

craig, October 2009

Gareth,the interior light switch usually has 3 positions: 1- on all the time,2- off all the time, and 3 -on when a door is open. I'd say there's a short in the back wiring, probably near a door -activated switch button, so current can flow to earth as if the door is open. The front seems ok,if I understand you correctly. You need to put the main switch in the "off when doors are shut position" and fiddle around the door button at one open door at a time, with the other doors shut .

Martin, October 2009