Corsa 2008 heater lighting issue

[Brod2610]

Hi all,
Im after some help regards my heater switch lighting

I recently replaced my radio to a pioneer radio, since then, the heater lights don’t come on with the headlights

I have checked the bulbs they’re ok. I have 12V at the bulb holder behind the switches when the headlights are on, so the only thing I can think of is I have lost a ground at the bulb holder.

this is backed up by the fact that when I do a continuity check between bulb holder and ground, there’s nothing.

does anybody know where I have lost this ground?

I am missing the following wires from the radio I installed,
Green - canbus
Cream - canbus
Brown - ph +
Blue - ph-
Black - mute 

I have continuity checked between all of these cables and ground, and I’m getting nothing.

I hope I’ve made some sense

cheers