Sentrawagon

ok I think I have a problem with my reverse lights when I have all my lights off and I put it in reverse they come on but as soon as I turn on my lights they turn off (reverse lights), so that's my first prob second one is that when I put it in reverse and start to move theres this werid clunking sound from the front but it's only when I'm in reverse so if any one can help me out it would be greatly appreciated thanx

James