Jaguar Repair: 1975 XJ6C Dash board and brake lights, chevy conversion, instrument light

Question
Coupe has Chevy conversion. 5.7 liter & 700r4 tranny.  In the past week, the dash board lights as well as the brake lights have stopped, started, and stopped working again.  I checked the fuses under the driver side panel.  All fuses are good.  I was told there were fuses on the passenger side panel.  I have not located them. I've owned the car for about 2 weeks.  Can you point me in the right direction to trouble shoot.  No manuals...but I have a multimeter.  Thanks...Richard

Answer
Sorry Richard, I don't have a 75 XJ-6 diagram but Jag usually runs the power to the instrument lights from the light switch to a fuse and then on to the instrument lights rheostat and on to all the lights.

If your brake lights go out at the same time it does sound like a fuse problem since the instrument light system would have nothing to do with the brake light circuit except possibly a fuse.

Looking at a fuse is not sufficient, you must check for power on each side of a fuse when the problem is in it's failed mode.

Howard