So, with the Dome light switch 'OFF', on the test we ran...we expect:So I turned my meter off and back on and it beeps on all but B
1) to hear a beep on A because there is just a wire between the PS (right) side of the Dome fuse slot and point A at the switch...if we did not hear a beep, that would mean that there was a short (a break in the wire and the bare wire touching ground) along that path...but this isn't the case...so we know this path is good and there is no short here.
2) we expect NOT to hear a beep at point B...because with the switch 'OFF', it is open...so there should be no current allowed to flow to B. Since we DID hear a beep at B with the switch 'OFF', we must suspect a short somewhere between A and B..the current is somehow bypassing our closed switch.
3) we expect NOT to hear a beep at point C...because with the switch 'OFF', it is open...so there should be no current allowed to flow to B. Since we did not hear a beep at C, there must not be a short in the switch between A and C
The only thing that would invalidate conclusion 2 is if you accidentally chose a point B that was accidentally touching the middle 'OFF' tab of the switch...