Wiring Aux Backup Lights

I know I've seen some posts about the short-story description about this topic, but am hoping for a bit more info.

Background - have some electrical knowledge, but not tons and want to use this to get more comfortable.

I snagged a pair of Nilight flush LEDs that I want to wire in as auxiliary back-up lights (don't need anything fancy) and want to wire them directly with the backups. My question is this - what is the process to do it? Is it something as simple as opening up one of the tail-lights, tapping into the hot line, grounding, and then running the second light in series? Or is there something more involved (relays, battery-run, etc.) that I'm missing. Any and all input is very appreciated!

Tagging @JaCado and @GHOST SHIP cause I know y'all have solid hardware knowledge here.

 

To do most anything to supplement the stock setup, you'd probably need to swap the stock bulbs to low draw LEDs.

There's some stuff going on here, esp with what @mesojdm just posted on the last page:
https://www.tacomaworld.com/threads/tail-light-mod-both-lights-used-as-brake-and-signals.471450/

I did this with a prototype harness:
https://www.tacomaworld.com/threads/back-up-light-installation-link-and-bs-thread.569289/

The power going to the stock reverse light (921 incandescent) was less than the Rigid Ignite.

 

Oh damn! I remember these threads too just couldn't find em - (https://www.tacomaworld.com/threads/rigid-ignite-led-pod-rear-factory-bumper-install.493316/) in particular works for what I'm going for!
Cheers!

 

Why not just wire them independently? Otherwise you'll be blinding everyone behind you every time you hit reverse.

 

Awesome!

I had a tough time finding them, that was why I created mine.

 

Grabbed low-wattage ones, they're about the same brightness as my fogs (which aren't too bright) so I'm not worried. I have the really bright ones on the cab. Don't want to flip a switch to have them activate

 

The Ignite with diffused lens is a bit bright, but I would not call it blinding.

 

aand that's not even that I'm using. The ones I snagged aren't that bright and I got a diffuser for em too

 

You should be good to go.

 

That's the plan - looks like I'll need to nab a relay and fuse too but oh well. Better safe than sorry!

 

Check out your draw first. If you swap the stock lights to LEDs, you might be able to power both without a relay? The 921s are 17.9W, pulling 1.35A each.

The Ignite pulls 0.85A. So if yours are a lower wattage, you got at least 0.5A to play with.

 

Not doing bulbs, just putting in 2 pods as additional lights. My lights should have the same draw each, which would put the combined below the 5 amp fuse - should be ok, ya?

 

I wired my flush mount ignite directly to reverse wires. No issues. Love how bright they are, if people want to stare at them when I'm reversing that's thier problem! Lol

I thought about running separate wiring to have them on demand. But I'll just leave the truck off and in reverse (MT) when loading my small boats in darkness.

 

With mine, I tied into the trailer harness rather than the reverse light circuit.

I justified this by saying I don't intend to tow a trailer so the small LED draw of my small LED reverse lights will hardly be enough to cause any issues with power.

 

You can tap the OEM backup light's positive to power your LED lights. The current draw from the new LEDs is likely small enough to not cause any issues.

That said, I would do it with a relay & a dedicated power source line from the battery.

1. Run an appropriately-gauged wire from the battery to the rear of the truck.
2. Put an inline fuse at the start of the wire on the battery side.
3. Grab a standard automotive relay.
4. Wire from the battery powers the relay. Power for new lights goes to relay's output. Ground from new lights goes to relay's ground, and also to frame. Tap the OEM backup light's positive and connect that to relay's witch. Ground the relay to the frame, too.

When you turn on reverse, OEM backup lights will act as a switch to turn on the relay, which will let the new backups lights draw power straight from the battery. No risk of overloading any circuits, and everything's protected behind the initial fuse.

 

With the stock bulbs pulling 2.7A together, you only have room for 1.15A pods (each). That's why I'm saying something like these (921 direct swap) would be good:
https://www.superbrightleds.com/mor...BEZgFa0_SThd8TKbLBVWw376XwhGRCP8aAgbsEALw_wcB

They're only pulling 0.05A!


Just a note that I am using 13.3V in my calcs. Going with 14V will give you more cushion, but I've found the truck oddly charges not much above battery voltage:

 

I've got one S2 sport flush waiting until after Christmas to install. It pulls 0.9 Amps.

My plan is to use two add-a-fuse taps and a diode on each source to power the light from both the Bkup Lp No.3 fuse and the Cargo LP fuse under the dash.

It would go either with the reverse lights or if the cargo lights were turned on, and diodes would keep it from back powering the other circuit..

(not the arrow)

 

3rd Gen trucks have there own 15 amp fuse and relay for the BU lamps/circuit, unlike the 2nd Gen which has a multi-shared 10 amp fuse.(some +12 have a separate fuse n relay for the tow connector for BU lamps)