2000 tundra alarm/remote start

I unplugged both of those harnesses but the only thing that went out was the speaker (when #2 was unplugged). I do think the door locks are on the lower plug (#3 in the picture) because when I unplugged it the locks did not work. Should the WHITE/ blue wire read negative when all doors or closed or when the door is open? I thought negative when the door is open but maybe my multimeter is getting screwed up because of bulbs being in the circuit?