I have a 92 XJS V12 and my headlights are always on I had to disconect the battery so it wouldn't die. Even if the switch is in the off position the headlights stay on and they stay on in every other spot on the switch. All the other lights on the car work as well. Any help is appreciated. Thanks

 

First thing to do is check the headlight relay is not stuck on. The headlight switch operates a relay it does not operate the lights directly.

here is a link to the elecrical guide for the MY92 http://www.captainjaguarscathouse.co...ec%20Guide.pdf

 

I put a new headlight relay in and the headlights stayed of for about an hour and a half then came back on and wouldn't stay off so I had to disconnect batt again. Any other ideas? Thanks

 

Disconnect the power wire from the relay to the headlight the headlight should go out. Reconnect this wire and then disconnect the power from the light switch to the relay (this is the wire that makes the replay activate). Post the results.

I would also check the wiring around the area if there is something amiss when you disturbed the wires give them all a good rattle.