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I'm not really knowledgeable using a multimeter. I got a cheap one to try to figure this out though. I'm trying to hardwire a dashcam that uses a DC input plug. I got a "MirrorTap" which is supposed to tap into the molex plugs on the back of the mirror. Does anyone happen to know which plugs the red and black wires should go to get power? A picture would be even better. I believe I can figure this out using the continuity test with the multimeter, by going one plug at a time, to see which is hot when the accessory power is on.
Electrical can be intimidating, but once you've done a few things, the confidence you obtain makes it worlds easier.
All you need to do to check for power is to place the multimeter on the V for volts setting (if there's two of them, the one with a squiggly line above it is for AC which is for housing electrical, there should be another one with a solid line with a small dashed line and that's for DC which is vehicle electrical).
Go ahead and pull the plug apart you want to test, and turn the car on to accessories. Place the black lead on to a good ground which basically means any bare metal of the vehicle itself. If you look under the dash to where your left foot rests, there should be a few good points, or even the bolts to the door hinge, just anything that's unpainted metal.
Now take the red lead and probe the connector until the multimeter reads 12 volts. Once you find one, then turn the car back off and test the same wire to make sure that there's no longer 12 volts to ensure the accessory won't stay on and drain your battery.
I tell you all that just to give you a fundamental idea of how to check for power if you ever need to, but in all honesty, there's a much easier way for you to supply power to an accessory, that's also 100% removable, and protects the item, with no problems: add a fuse. I'm quite certain this is the one you need. If you look under the dash, there's a fuse block there. Pull the "meter" fuse which is the fuse for the dash gauges like speedometer, plug this in, put the old fuse back into one of the spots, put a 5 amp in the other spot, and the wire coming off of it is your power supply wire to your accessory. It's as easy as that.
Thanks for the info. I'm trying to wire a dashcam into the back of the rearview mirror. I think I can just stick the red and black wires into the appropriate molex plugs back there. This way I don't need to run the power wire down the A-pillar. I found this post from 10 years where someone wired a radar detector in this manner. It looks like they put the red wire into left-most molex and the green wire (is this same as black wire?) into the next molex to the right.
The funny thing is, years ago I actually had done this with a V1. But it was so long ago I can't remember how I figured it out. Someone might have simply just told me where to stick the wires.
Ah ok I gotcha man, the pics in the link really help me get a better idea.
So yeah it does appear that the wires are set up the way you have suggested. But in any event, you can use the method of checking for voltage to ensure you get the right ones hooked up correctly.
Are there only 2 wires coming from the dashcam? And did it come with a diagram at all? If so, it should be super straight forward in that the red should be 12 volt and the green should be ground. I can also try and pull a wiring diagram up tomorrow at work to narrow down the wires you'll need from the car as well if that will make things easier for you?
I really appreciate your help! This is the "mirrortap" DC plug that I'm trying to fit into the rearview mirror: https://www.blendmount.com/mirrortap.html. It's supposed to be able to power a 12V dashcam and they list blackvue as one of the supported cams (which is the cam that I got).
So I *think* I can put a wire into each molex plug, and using the continuity test, see if the wire provides power? Perhaps it's trial and error to see which molex plug is the proper plug. If that first plug provides power (as the pictures show in that old post) where would the black wire go?
So for the power wire, use the voltage check I talked about. But for ground (black wire) this is where you use continuity tests. Put the multimeter on to the Ohm setting, likely an omega symbol. Place either lead on to a good ground of the chassis, like what I mentioned earlier, pretty much and bare metal like a bolt. And probe the other wires. When you find the ground, the meter should go to zero ohm. All the other wires will show OL which stands for Open Lead or Open Loop.
But again, give me a few hours and I'll look up some wiring diagrams and point you to the right wires.
Also, I'm looking in to your other post about your code so give me a few min on that too and hopefully we can get you situated there as well.
Very nice! Glad you were able to get that figured out. I apologize on my delay for helping, ive had a busy couple days at work and havent been able to spend some time looking for info.
06-24-2018, 10:53 PM
