Hi boys,
I am a bit late for this topic, but I thought I'd throw in my 5c worth anyway - maybe more for the future searches.
(and - yes, I am the owner of VIOFO A119v3)
1) It does NOT matter at all for this model, which MiniUSB socket (on the dashcam or on the GPS module) you plug your miniUSB plug from the HK3 into - the power, gnd and signalling (ID) pins are bridged together on those sockets when DashCam is mounted on GPS module. The only thing to remember is that if you want to connect your dashcam to PC for file transfer, you have to use a proper signalling 4-wire MiniUSB cable and connect it to the dashcam socket ONLY - the GPS module does NOT have the Data+ and Data- connections.
2) If you look at the four contact pads on the GPS module (where the dashcam spring-load contacts connect to), they will carry the following signals (starting from the center hole going towards the edge of the GPS module):
Vbus (+5V), GPS stream, ID, GND (closest to the edge)
.
(but even if you don't look at those four pads, they will still carry the same signals anyway...
)
3) When the MiniUSB plug on the end of the properly wired up HK3 power cable is plugged into the GPS module, the following voltages on those 4 pads should be present and considered normal :
GND is electrically connected to the body of your vehicle (or to the (-) terminal of your car battery for that matters)
Vbus (dashcam supply) should be measuring +5V (+/-0.5V) relative to the GND (GND pad or vehicle body)
GPS stream should measure (relative to the GND) jumping voltage anywhere between 0V and 2.5V - this is the serial comms stream from the GPS to the (currently unplugged) DashCam.
ID pad should measure (relative to GND) less than 0.5V when the car is off (Accessories voltage is NOT present) and more than 4V when the car is running or when your key is in ACC position (radio is going). This signal tells the DashCam to switch between normal (road) mode and parking mode.
4) When A119v3 is powered from the cigarette lighter using it's own 12V->5V cigarette lighter plug and the long USB cable from the purchased set, the parking mode to- and from- switching logic is completely different to that when powered from the HK3 kit. Be aware of that.
5) I agree with jokiin that it was very forgiving of V119v3 to continue working after having been powered with 12V instead of 5V. You should donate $20 to the charity.
Hope someone will make use of this info.