My driver-side sidelight has gone much duller than the passenger-side, so much so that at distance it hardly looks like its working. Now I would have thought that if the bulb had gone it wouldnt work at all? Im going to try changing the bulb first just to make sure, but is there a guide anywhere that you can point me to on how to do this please? Also if anyone has any suggestions on what may be the trouble if its not the actual bulb it would be very much appreciated? thanks.