I have a 1987 fox in which the instrument cluster lights will not work. This runs off fuse #24 and I have looked at the wiring diagram in my bentley manual, and I dont know why the fuse keeps blowing out. When I turn on the running lights the fuse imediatly goes out. Thanks for your advise, and I love your manual Its helped me through several projects.
The short answer is that the fuse blows because too much current is flowing through it.
Is it the right size fuse?
If it is, then you must have a short somewhere. You're going to have to follow that wire from the switch to the lights and look for short circuits. One thing you can do is to remove all the bulbs, then ohm the wire to ground. With the light switch in the OFF position it should read infinite ohms with all the bulbs removed. It's quite possible that someone has connected a radio or other device to that wire somewhere and that's what's blowing the fuse.