Hi Guys,

So I sat down with the circuit diagram from a haynes for 3 hours and I
htink I have found the problem, on paper at least. I dont know how to
physically look for it now.

Heres how the short HAS to look like to fit all observational evidence:

+___________________________________
| |
| |
15A Fuse 15A Fuse
Marker, Instr Lighter, Interior
lights etc light, radio etc.
| |
| |
| ___________ |
| / short |
headlight / Lighter, Radio,
switch / Interior Lights etc.
| / |
|_____| |
| |
| |
Marker lights, |
instrument |
lights etc. |
| |
| |
------------------------------------------------

So since he short bypasses both the switch and fuse, the marker etc stay on
because the circuit is completed from the always live (no switch)
lighter/InteriorLight path. So taking the fuse out or the switch make no
difference. But since the lighter fuse is now in the picture, taking it out
switches everything off.

The headlight switch now turning the interior lights/ radio etc on and off
is also explained because when the lighter fuse is removed( which I had to,
to kill the always on lights) , the only path is through the marker fuse.
And the interior lights/Radio simply becomes a parallel circuit to the other
, going through the same switch.

phew.
But now where should I look physically to find this in the car!