oh dear... get some help before you hurt yourself..

hes got it on AC Quench ... thats not going to work

the ~ with the line means AC. the 12v setting will be DC. mV / mA etc is useless to you with your current skills

wheres the 20V setting ? highest i can see is 12V. doesnt look like your fancy fuse checker is up to the job really but the AC setting will let you test GI ( put one each side of the lamp) and the 12V DC will let you test the controllled lights. ( red to the lamp on the side that does not have the individual wire colors and black to the cabinet braid)

just be aware.. that rectifier pcb you'e poking at has 200V DC on it.. thats MORE DANGEROUS than trying to mess with your house wiring. 230v AC will let go as it crosses phase.. DC just hangs on and keeps punching you.. dont put your toy meter places you arent real sure about. even coil voltage will be too much for it.

oh nice that makes much more sense on a bigger pic. couldnt work out why it was limited to 12v ..