looking at the internet for the connection diagram nung AVT TV Tuner.. I see na yung ACC ang naka linya na may fuse... question uli.. bakit yung fuse naka linya sa ACC at hindi sa +12V?

last time I tried to troubleshoot yung AVT TV Tuner sa car.. all i did was to get voltage across red wire and black wire... red wire yung naka linya sa fuse... at that time, I assumed that the red wire was +12V.. now mukhang may sariling color code pala... kung base sa bagong AVT TV Tuner connection diagram.. the fuse is on the ACC line... then.. dapat pala I have to double check the wirings uli...

dapat pala ginawa ko... check the voltages when the key is on OFF, at ACC and then again at ON and STARTED... ang ginawa ko last time was just get the voltage at ON (started)....

balik sa question.... so ACC ang nag trigger ng ON ng unit... pero once na nasa ON na ang susi may signal pa rin sa ACC?