How do I *properly* join three 16 gauge stranded wires? (1 Viewer)

[CharlieS]

I'm working in a wiring project for the 200 (plug and play roadvision rear lights) and the wiring requires a few three way splices, or at least splices into the middle of a wire.

I'm essentially adding a harness into the middle of my trailer lights that borrows the signal to drive the roadvision lights.

To do that I have two factory connectors that fit the male/female trailer harness. They need to still carry the signal, but also have a wire off them that goes to the Curt 2 to 3 signal splitter and onto these aftermarket lights.

I want to do it correctly though.

To clarify that statement: I don't want any T-Tap connectors, wire nuts, etc. I'd like this to be as professional as possible, like the level of quality that an A&P professional would put into their work.

Can anyone share a link, video or diagram of a proper 3 way splice, or proper splice into the middle of a wire?

 

[TeCKis300]

Youtube university has some great tutorials. There's t-tap strategies for solderless, solder, heat shrink, electrical tap, and possibly even more combinations.

Here's a good one to start with

 

[hankinid]

What's the distance between the connectors in your picture?

I can give you a info on either crimping or soldering.

Not an A&P but I did teach A&P's methods of wire splicing at the China Lake Naval Weapons Center.

 

[CharlieS]

Thanks guys!

The plug and play bit is only going to be maybe 4 inches long (maybe even shorter if I can still work with the wires). It will go inline between the vehicle wire harness and one plug on the factory tow connector.

 

[CharlieS]

I did the bare wire splice thing and am trying to figure out if I should solder, or just cover with liquid tape. Any opinions? I heard somewhere that solder isn't ideal in automotive applications (although I'm embarrassed to admit that I've used it here and there like to splice wires).

 

[grinchy]

Solder is perfectly acceptable when done correctly and covered correctly.
Lately I’ve been crimping three ways - twist together and crimp. The audio install style crimps seem good for this, though a shrink style would be even better. I’m sure there is all sort of discussion on why this isn’t the best, but it seems to be working for now.

 

[Fisher23]

Solder them for sure. I solder my camera wires.

They also have a product called liquid electrical tape in HD or Lowes you can paint on the connections and it's water proof.. Or you can use tape.

 

[bloc]

The "problem" with solder is the very sharp/defined end to the support of the wire in the solder. This puts all the strain of movement in one tiny spot, eventually leading the wire to break at that point. This is still very, very rare.

The proper way to splice wires is the same way toyota and everyone else does their splices and connectors.. a high-quality crimp. This squeezes the strands together.. if you use enough force it compresses the round wires into a hex dramatically increasing the surface area... but there is still a relatively long transition from the supported wire within the crimp to the unsupported wire out of it. This gives extra room for the wire to flex gradually and avoid failure.

Again, properly set up solder joints still don't fail very often, but I've moved to almost exclusively crimping things.. and it turns out it works great not having to mess with flux, or deal with corroded copper surfaces that don't want to wick solder.

This shows some of the tools

How-To: Properly Crimp Wires and Terminals - Hughs Hand Built

I posted the below pic to our Instagram and Facebook page earlier today… The first comments pretty much nailed… Can we really beat a dead horse? I mean, it’s just basic wiring right? Apparently that bad wiring horse still has some life left in him… Finish him off! Do your wiring...

www.hughshandbuilt.com

I've started using brass "open barrel splices" provided in kits of a few sizes. Then glue-lined heat shrink over that. They aren't much larger than the insulated wire once finished and very, very secure. It is a little fiddly getting the correct size splice into the correct die in the tool.

Here's the definition of going down the rabbit hole on this topic. Be sure to scroll to where they show how they twist the wires in the harness alternate directions depending on the layer of wires to allow a very thick harness to flex evenly. It is nothing short of art:

Motorsports ECU Wiring Harness Construction

 

[CharlieS]

I split the wires, wrapped in opposite directions, soldered, and coated with liquid electrical tape (not as tidy as I like) and will wrap with loom and tape. Probably not okay for nasa or an airplane, but will be okay for brake lights.

 

[bloc]

I split the wires, wrapped in opposite directions, soldered, and coated with liquid electrical tape (not as tidy as I like) and will wrap with loom and tape. Probably not okay for nasa or an airplane, but will be okay for brake lights.

View attachment 3020751View attachment 3020752

That'll work great

 

[kcjaz]

@CharlieS, I used these for my trailer harness/Dissent install. They worked great, easy and fast. Nothing wrong with what you did though.

https://www.amazon.com/gp/aw/d/B07HCNTZ2Z?psc=1&ref=ppx_pop_mob_b_asin_title

 

[CharlieS]

Thanks everyone.

Final product: