LED Switches - Where to tap in?
 

So I made my own rocker switch panel to operate my Air Horn and another for the Compressor. The switches are 5 pin dual LED switches, and I can't decide (nor know where), if I want to wire it to the dimmer (dash lights) or just to the accessory (when the ignition is on).

Is anyone able to give me input on which method to do, and where I can find the easier way to access the wire I need to split into?

Thank you!