terrano 2 reversing lights

[jeffb7449]

I have a 99 terrano 2 with 2" lift, a safari snorkel and 30" kumho mud tyres, 2.5" zorst and steinbuer chip. Recently the reverse lights stopped working. I have checked the fuse box, light bulbs etc. I unplugged the revers switch and bridged the connection still no go. What could be the prob??