How to wire aux lights?

You can make it as complicated or as simple as you want, it's your truck. Judging by the first post, you like complicated and over thought out, which is fine. I answered your original question as simply as possible with a simple circuit, you can follow that or do whatever you want as I don't care either way. I didn't offer an example of a simple working circuit to get into a debate on what type of lights should come on at certain times, what direction lights should be pointed, and other choices that remove other people's freedom of choice. You wrote you wanted aftermarket lights to come on automatically with the reverse lights and that's exactly what that simple circuit does in my crappilly drawn diagram. Have a great day.

 

Don't tap the wiring in the tail light. You're asking for trouble down the road. Run new wiring with a relay and fuse to the battery. Use the existing wiring to turn the relay on. It's right there under the threshold trim. It's in the cab, it'll stay dry.... We hope. Lol.

When making the tap, strip your wire a lil more than an inch. Then on the wire you want to tap, you carefully remove about 1/2" of insulation and wrap your wire around it. Solder it.

 

I tapped my led pods off the reserve wire off the trailer plug. Has been like that for 3 years without issue.

 

I have my reverse LEDs running to a relay which is triggered by the reverse light wiring and a switch. Both are diode isolated so I can switch on my rear lights independently than activating through reverse. My upper side shooter pods and bumper LEDs all turn on during reverse.

 

Trailer harness is cake for getting relay taps.

My opinion, manually triggered aux lights suck. I don't know why people spend stupid money on those "pods" so they have a Uber cool switch to push manually. My spots and reverse are triggered by my truck to come on automatically, can be manually set to off, or manually turned on with a 3 way switch.

Nothing better then being able to hit the LED spots by flicking the hi beam stalk. You can actually use them while driving instead of having to hit two buttons to go back to low beam.

Three way switch that takes switched 12v from the reverse wire or a constant hot, through the switch which gives you the three positions, which triggers the relay.

You can even by a Blue Sea fuse to come to come right off the positive post so it looks real clean.

 

Mine turn on only when it's dark out. Don't need'm otherwise

 

If wiring the aux lights in only temporarily,
how are people doing that?

Tapped into the tail light reverse wires? Or the tow harness plug reverse and ground?
If so, did you find out what wire gauge it is, to pick a matching wire gauge and crimp?

I'm trying to figure out whether to use a 3-way splice, or Scotchlok, and which size to get (such as red 18-22awg, which may be too small)
Scotchlok is definitely cheaper. A couple bucks for a pack of many, versus $18 for some 3-way crimp connectors.