I have a '98 VW Caddy, it has recently.

I have a '98 VW Caddy, it has recently developed a problem where the dash doesn't light up at all. The battery was old, so replaced this, nothing.
Occasionally, the dash will light up and then it'll start, but the problem has got worse, and now can't start at all.

Not sure if its a relay or ignition switch, or simpler still, a wire that is not carrying power? Any help much appreciated.

Thanks,
Alex