where is the reverse lights switch on my 1998 vectra?

Hi,
On the gearbox bellhousing you will see a screw in connector. A two wire lead goes to the connector, disconnect them and bridge the connections. With the ignition on you should see your reverse lights on. If the system works like this you can say with some confidence that the switch is the culprit.
Cheers now

Ken Chapman
May 2007