Cargo Lights on with Reverse Lights

pgamboa · June 30, 2017

This is awesome with Towing Mirrors that have Cargo lamps too!

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Davidj101 · July 19, 2017

Just did this mod yesterday, and it is awesome.

I wondered if having the upper cargo lamps on would reflect too much light when reversing, but they don't at all. And those combined with the mirror lights, increase camera visibility immensely.

pgamboa · July 19, 2017

Just did this mod yesterday, and it is awesome.

I wondered if having the upper cargo lamps on would reflect too much light when reversing, but they don't at all. And those combined with the mirror lights, increase camera visibility immensely.

Also great if you have bed lights too!

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Davidj101 · July 24, 2017

I do have bed lights and that just adds to it.

I used a 1N5408 diode, which is a 3 amp diode, but it has slightly smaller diameter legs compared to the 1N4004 (1.3mm to 2.3mm) which makes it easier to insert beside the crimped connector. It stays in place well.

I ordered 20 of them and I'm going to keep an extra, so I have 18 that I'd be willing to send anyone that needs them. Just PM me your address and I'll drop one in the mail to you. Free of charge!

Ravenkeeper · August 3, 2017

I did the mod for the cargo lights to come on with the reverse lights. Love it. Cargo light switch illuminates when the truck is in reverse.

Of those that have done the mod the other direction (reverse lights on with cargo light switch), what all have you noticed about turning on the cargo lights? Does the backup camera come online? Engine running or not? Or any other quirks that you've noticed since the mod?

Edited August 3, 2017 by Ravenkeeper

Lamby66 · September 19, 2017

Has anyone doing this mod, or a version of it, find the location where the towing mirror cargo leds are tied into the rest of the cargo light circuit?

The upfitters guide says J302 under the left instrument cluster... That is not really too helpful as there is a mile of bundled wire under there....

I REALLY want to switch the use of these leds with a SPDT so they are Normal/Off/Reverse. I have a more complex but more useful control of my cargo lights operated by my backup lights and a latching timer circuit but that is only for my bed cargo lamps, as I cant find where I can turn off those annoying mirror LEDS separate from the high mount cargo light (which I would also like on with my circuit)

Anyone able to help?

Ravenkeeper · September 19, 2017

Has anyone doing this mod, or a version of it, find the location where the towing mirror cargo leds are tied into the rest of the cargo light circuit?

The upfitters guide says J302 under the left instrument cluster... That is not really too helpful as there is a mile of bundled wire under there....

I REALLY want to switch the use of these leds with a SPDT so they are Normal/Off/Reverse. I have a more complex but more useful control of my cargo lights operated by my backup lights and a latching timer circuit but that is only for my bed cargo lamps, as I cant find where I can turn off those annoying mirror LEDS separate from the high mount cargo light (which I would also like on with my circuit)

Anyone able to help?

They are considered "Puddle Lights," GRY8 on the BCM. Run the diode from BRN26 to GRY8, stripe end in GRY8. You may need to jumper PNK26 to GRY8, as well. I think that PGamboa did this with his tow mirrors, he can confirm these, when he checks in.

Lamby66 · September 19, 2017

Ravenkeeper, thanks for the info, but tow mirrow lights are not puddle lights but blinding backup lights. I want to keep these off most times. I need to isolate them from the factory cargo lamp circuit.

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pgamboa · September 19, 2017

Ravenkeeper, thanks for the info, but tow mirrow lights are not puddle lights but blinding backup lights. I want to keep these off most times. I need to isolate them from the factory cargo lamp circuit.

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Puddle Lamps and Cargo Lamps are two different circuits. In the BCM, the Brown Plug (X6) - Pin 26 is the Cargo Lamp circuit that BCM switches on/off - BUT, if you look at the diagram, it is a ground circuit that is being switched. That's treason why the diode faces towards the Pin 26 of the Pink Plug.

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Lamby66 · September 19, 2017

Pgamboa, I understand the circuit. I wired my cargo circuit to back feed from the trailer backup light circuit and a timer based button in the bed. I installed a diode to prevent the cargo circuit I designed from feeding the center high and mirrors.

In an ideal design, I would like to include the center high light in my cargo light circuit but keep the mirror leds from coming on. A passenger compartment mounted double pole single throw switch would work prefect IF I can find where J302 is located.

I was hoping there was a gm tech on here that would have access to the harness routing drawing to tell me where J302 is located. Per the upfitter guide, this is where the center high cargo light is tied to the towing cargo light circuit.

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pgamboa · September 19, 2017

Puddle Lamps and Cargo Lamps are two different circuits. In the BCM, the Brown Plug (X6) - Pin 26 is the Cargo Lamp circuit that BCM switches on/off - BUT, if you look at the diagram, it is a ground circuit that is being switched. That's treason why the diode faces towards the Pin 26 of the Pink Plug.

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Yep. I had others ask why the diode was facing the way it was and thought is was a battery + switched circuit. So took that opportunity to explain.

Good luck finding J302. I have not been able to intentionally find any jumper harnesses. Lol. Always by accident.

Upfitter says "J302 is in the passenger compartment, under the left side of the instrument panel"... lol. Whatever that means. Most harnesses have a harness routing diagram but this one does not.

Good luck, hope you can find what you're looking for.

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Lamby66 · September 19, 2017

Yea, I think maybe my fox and hound toner might be able to help with this. There might be quite a bit that tones though considering this circuit goes EVERYWHERE ;-)

Thanks again for your help guys

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Hswerdloff · November 9, 2017

Alright so I’ve been really wanting to do the cargo light - reverse light mod but i can’t find the right wires in the BCM. I can’t tell if the original post is for a NNNBS, but I have a NNBS. 2011 Silverado 1500 Z71 if that makes a difference. I’ve searched all over google and can’t find a diagram. Here’s a picture of what my BCM wires look like. The site won’t let me load more than one pic. Any ideas?

Edited November 9, 2017 by Hswerdloff

Neallynein · November 9, 2017

I had an issue with getting this to work. I bought the 1N4004 diodes (chinese got a 25 pack for like $1.25). I put them into the pins that people above mentioned but it did not do anything. i have them in as far down as possible on both sides. Is there something that i probably missed? Or maybe just one bad diode? i have not tried any others yet

JONES424 · November 9, 2017

38 minutes ago, Hswerdloff said:

Alright so I’ve been really wanting to do the cargo light - reverse light mod but i can’t find the right wires in the BCM. I can’t tell if the original post is for a NNNBS, but I have a NNBS. 2011 Silverado 1500 Z71 if that makes a difference. I’ve searched all over google and can’t find a diagram. Here’s a picture of what my BCM wires look like. The site won’t let me load more than one pic. Any ideas?

I do not have an answer for you but what happened to your wires?