When the lights are on, the panel lighting is regulated via the dimmer roller on the headlight switch. Hence why it can appear to go off when you turn the lights on.

First thing try adjusting that.

If that doesn't sort it then you might want to swap in another headlight switch to see if that changes anything.

The centre console lighting on my 2000 Corsa B is screwed and I'm gonna tackle it next week. I know the heater control lighting is just 2 bulbs that need replacing, but the MFD is throwing me a bit and I don't know what to do.

When the lights aren't on, the MFD is fine, it shows the time, temperature etc. As soon as I turn on sidelights or dipped, the MFD knocks off. It's been like this since I bought the car in the summer. The only exception was christmas eve and christmas day when it was working perfectly. Once christmas was over it went back to the way it was. Creepy ey? I've got 2 options really: Try to fix the circuit board, or buy a replacement MFD off ebay. My only worry is it might not be the MFD that's faulty but the wiring that plugs into it.

My questions are could it be the wiring, if not what exactly on the board needs fixing, and would it be easier/cheaper to fix it or buy a replacement unit?

Cheers.