Boost gauge wiring

[SHUk]

I have an electronic boost gauge with adjustable dimming feature.

I know I can wire it into the dashboard adjustment switch, but am uNsure of which of the five wire going into the adjustment I need to splice into?

Also, can I take power and Earth from the same switch?

Thanks

 

[Stuart B]

I am in a similar situation here. I want to buy a boost gauge and they are backlit - is it a simple wiring solution.
I do have form of not being good with auto-electronics, when I created a new power outlet in my alfa it dimmed the lights when I plugged something in. and in my camper van I burnt my fingers and started a fire in the fuse box when testing an earth for the temp sender unit + additionally I am coloured blind. but if it is something "inline" I am okay with that - eg successful Radiator Fan override on a fiat cinqcento.
The dash lights are always on on the S3 so I do wonder whether I simply hook up on the dimmer switch?