Well from the pdf posted here: Terminals 15, 30, 30g and 30g_f

"Terminal 30g:
Terminal 30g is controlled by the CAS. When the overall vehicle is wakened by an operation of the user, terminal 30g is
switched on. Terminal 30g is automatically switched off after a codable after-run time (e.g. 30 minutes). The after-run
time starts with the event terminal R Off. As in the case of terminal 15, a relay in the distribution box is activated by the
CAS via a semiconductor switch. The relay of terminal 30g switches the battery voltage to approx. 18 fuses in the
distribution box."

I think you will want the 58G, but I can't find much info about it.. its also a much smaller wire than 30G. Maybe you will need to get the power from 30G but signal it from 58G?

If you are replacing lights, why don't you just use the ones that are powering the existing lights?