vahaull vectra estate t reg reverse lights not working?

hi my reverse lights have stopped working, anyone know what the problem might be? fuse been checked, bulbs been checked so no problem with them, aparently there is power going to the reverse switch then stops after that area, would be gratefull if someone could help, dont want to put it into garage again, the car has cost me a fortune this year getting new engine sensors etc.... would be greatly appreciated for any suggustions, thanks