Which wire is for reverse light in trailer harness plug)

[SDHNTR]

Need to tap into reverse light wire. Anyone know what color it is on a 2025?

 

[SDHNTR]

Or which is the hot reverse wire in the tail light?

 

[SDHNTR]

Anyone?

 

[T-Rob]

Not sure about the trailer harness, but on my 2025…the white wire is the reverse wire in the tail light.

 

[bigredaggie]

This matched my 2022

 

[tjg]

Need to tap into reverse light wire. Anyone know what color it is on a 2025?

Just put a test light on each one with vehicle in reverse.

 

[deepblack]

I have a 2024 402A and the taillights are the scales version even though I don’t have the feature. There is no hot 12v reverse wire. Had to use the trailer wire.

 

[SDHNTR]

What’s this mean? How can you not have a hot reverse wire in the tail light?

 

[deepblack]

What’s this mean? How can you not have a hot reverse wire in the tail light?

There isn’t just one reverse light, there are 3 or 4 meant to light up based on the load in the truck, or all of them when you are in reverse. So it sends a can bus message which determines how many lights to turn on.

This is why you have to be careful purchasing aftermarket taillights and wiring harnesses. Lightbars come in a “with scales” version.

 

[SDHNTR]

There isn’t just one reverse light, there are 3 or 4 meant to light up based on the load in the truck, or all of them when you are in reverse. So it sends a can bus message which determines how many lights to turn on.

This is why you have to be careful purchasing aftermarket taillights and wiring harnesses. Lightbars come in a “with scales” version.

Interesting. I’ve got a Morimoto license plate bracket boost bar. I wouldn’t think it would matter which one I tap into.

 

[bigredaggie]

The yellow reverse wire in the 7 pin trailer connector/harness should be a plain old 12V hot line regardless of if you have the fancy weight scale tail lights. That seems like the easiest thing to tie into for your boost bar. Yellow for reverse hot, white for ground (verify with a multimeter). With that said, the trailer connection wires are likely much heavier gauge than the tail lights and your boost bar wires, especially the white. Consider that when doing your splice you may need step down crimp connectors.

 

[SDHNTR]

The yellow reverse wire in the 7 pin trailer connector/harness should be a plain old 12V hot line regardless of if you have the fancy weight scale tail lights. That seems like the easiest thing to tie into for your boost bar. Yellow for reverse hot, white for ground (verify with a multimeter). With that said, the trailer connection wires are likely much heavier gauge than the tail lights and your boost bar wires, especially the white. Consider that when doing your splice you may need step down crimp connectors.

Yes. The gauge difference may be an issue for the connector, and I didn’t think about that. May just tap into the tail light instead.

 

[SDHNTR]

Ok so I found the hot wire for reverse in the tail light with a test lamp. It’s green and brown. This Morimoto has both hot and ground to tap into. Is it safe to assume the black wire with yellow tracer (the only black one in the harness) is the ground?

How could I confirm ground with a test lamp?

 

[bigredaggie]

Use the clamp on the test lamp that you would normally clamp to chassis and clamp it to the black/yellow GND wire. Then the test probe to the hot green/brown. A multimeter would be better but that should work, especially since a quick google search I just did confirmed your color findings.

 

[SDHNTR]

Use the clamp on the test lamp that you would normally clamp to chassis and clamp it to the black/yellow GND wire. Then the test probe to the hot green/brown. A multimeter would be better but that should work, especially since a quick google search I just did confirmed your color findings.

Thanks. I got it, and tapped into those two wires. Then I tested the pigtail and it was hot. Then plugged into the Morimoto led bracket, and nothing. It must be faulty?

 

[bigredaggie]

touch the morimoto leads across a 9V battery and see if it lights just to rule out your wiring job

 

[SDHNTR]

touch the morimoto leads across a 9V battery and see if it lights just to rule out your wiring job

Seriously? A 9v?

 

[bigredaggie]

9V should work though it might be dimmer than expected , 12v car or power tool battery would work great. whatever you have that can energize it to the 9-16V it’s rated for just to see if it works

 

[SDHNTR]

9V should work though it might be dimmer than expected , 12v car or power tool battery would work great. whatever you have that can energize it to the 9-16V it’s rated for just to see if it works

I thought about hitting the leads on the battery but was afraid I might short something out.

 

[SDHNTR]

Problem solved. The cheap little tap connector that was supplied by Morimoto was defective. The little strip of metal inside the connector on the ground side did not connect from wire to wire. Just a manufacturing defect. Swapped it out to a new tap connector and bingo. Go figure.

So for anyone who needs to know, the green and brown wire in your tail light is hot for reverse and the black with yellow tracer is ground.