Favourite method to splice automotive wiring?



  • I need to tap some 12v wiring in our tent trailer. I’ve found some good candidates to tap, but there’s not a lot of slack in the existing wires. One connection will be inside the trailer, the other will be underneath, so sealing is definitely on my list of priorities for that one.

    The wires that I’m eyeing current run to marker lights, and the porch light.

    What are everyone’s recommended ways to splice automotive wiring? I’ve read a bit on some of the snap-on taps, and won’t be using those.

    @dhylands @Ron_Ron @pierre



  • I’ve used those taps successfully on many vehicles for many years. In a damp location you can wrap them in good quality electrical tape.

    If you don’t want to do that and you have room to work then you can strip and inch of jacket off the original wire without cutting it. Wrap the bare end of the new wire around the stripped wire and solder in place. Clean off the Flux and tape.



  • Princess Auto has some heat-shrink tubing with adhesive inside it… Basically hot-glue in a polyolefin tube. When you hit it with the heat-gun, glue squirts out both ends and it shrinks tight. I’d trust it submerged.

    https://www.princessauto.com/en/detail/28-pc-3-in-dual-wall-adhesive-lined-heat-shrink/A-p8555591e

    I’ve had to repair a lot of inept things done with scotch-locks:

    0_1499241769909_scotchlock.jpg

    If you can find real Marr connectors (the kind with the setscrew, not twist-on Marrettes) throw a couple in your glove box. They’re a vibration resistant way to effect a field repair on vehicle wiring.

    0_1499241924501_Marrwirenut.jpg

    I’m pretty sure they are not supposed to be used for that, but it beats soldering the wires back together with solder scraped off the stereo circuit board, and a zippo for heat…

    Not related to splicing wiring… if you don’t already have some in your vehicle, head over to the plumbing department, grab a roll of all-round strapping:

    0_1499242261015_allround.jpg

    And a handfull of nuts, bolts, and tek-screws that fit the holes in the strap. You’ll thank me later when a muffler comes loose, or you need a bracket to re-mount a tail-light etc. I routinely use it to attach VESA equipped monitors to things without having to get a proper monitor mount, or to add safety straps to things that look precarious.

    The copper all-round is a great way to make ground connections. It solders easily, and lets you screw the component to the frame.


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