Headlight/Daslight oddity

[porthyt]

Evening,

Recently my dash lights have been acting weird. With the ignition off, I can turn the headlights and dash lights on and the light up the binnacle. However, as soon as I twist the key to start the interior/dash lights turn off but the exterior headlights stay on. As soon as switch the ignition off back come the dash lights.

I presume it's an earthing thing? Where are the dash lights earthed? Is it behind the glovebox? There is such a maze of wires it's hard to trace it.

Cheers
Josh