OP
KAS1
I was assuming there would only be half a dozen lights or so, I agree your method is the best way forward but I was trying to give him a sure fire way of eliminating light by light as he seems a bit stumped and your (the best method) just might confuse him if the lights are dotted all over the show lol
Whats with this test each bit individually malarky? Split the circuit in half find the faulty half, split the faulty half and find the faulty half of that etc etc until you isolate the fault.