I like making my own harness’ for car electronics projects. I’ve spent enough time upside down underneath a dashboard professionally to know that it’s best to minimize that. So I do as much as I can on the bench.
This is a simple one (it really isn’t even a “harness”), but I normally go overkill with projects and this is no different. I’m just hard wiring my dash cam into the Alltrack. I could just get one of these, and one of these, find switched power and a ground, run the wire and be done with it. However, I want to add a switch so I turn the camera circuit on even if the car is off. I also always use a relay, so that means I need to do a bit more work.
First I disassembled a USB charger I had laying around, snapped off the contacts and soldiered in wires. Then I drilled out the front enough to bring out two wires and fit a piece of heat shrink. I tested it and wired it to the relay. I will also be using fuse taps and diodes for the constant and switched 12v wires that will be used to trigger the relay. Then I trimmed out the red wire as I’m not using the negative trigger, loomed it up, and trimmed up the wires for install.
So now all I have to do is grab my constant 12v and ground sources, then find switched and constant fuses to tap for triggers, wire in diodes and my switch (which I think I will mount upside down in the plastic foot well “ceiling”). Diodes will prevent current from flowing back into the cars circuits if I accidentally have both trigger wires activated at the same time.
Anyway, just sharing because I like working with electronics and I can’t talk to anyone else about it. So i’m pitching it out here as we’re a creative, project based, bunch.