Wiring up LED Mounted back up lights.

[Firefighter94]

Mounted LED back up lights under my receiver hitch on 24 3500HD like all my trucks in the past. My mechanic in the past always wired them to power on with the reverse lights splicing into the back of the 7-pin harness. They cannot get any power when put in reverse? They are wondering if there is no trailer connected the computer wont power them on. Have any of you ran into this problem on yours? If so how did you fix it?

 

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[gemarsh]

That would be correct.

Tap into the reverse light circuit behind the tail light. Use the reverse light circuit to control a relay. Power the relay from the 7way 12+ wire (always hot).

 

[gemarsh]

Wire your "tapped" reverse light wire behind tail light to the relay terminal #86 called out as, "to positive trigger source" in picture.

Wire your "tapped" 7way 12+ to the relay terminal #30, eliminating the battery icon in picture.

The rest of the terminals are self-explanatory.

 

[Sanderson1582]

That would be correct.

Tap into the reverse light circuit behind the tail light. Use the reverse light circuit to control a relay. Power the relay from the 7way 12+ wire (always hot).

Why can’t you just tie them directly into the rev wire on the 7 terminal trailer plug

 

[gemarsh]

Why can’t you just tie them directly into the rev wire on the 7 terminal trailer plug

The T1's 7way isn't live until a trailer is hooked up. Exception to that is the 7way 12+ is live all the time.

I haven't chased down what signal, powers up the trailer control module when a device is plugged into the 7way. I'm expecting a ground signal.

 

[Sanderson1582]

I’m not doubting what your saying I know that the trailer plug is not activated. Until you hook a trailer to it, so I’m wondering how Putco is doing it with their light bar they have an adapter that goes in series with the plug to your seven pin that plugs into there light bar.

 

[gemarsh]

I’m not doubting what your saying I know that the trailer plug is not activated. Until you hook a trailer to it, so I’m wondering how Putco is doing it with their light bar they have an adapter that goes in series with the plug to your seven pin that plugs into there light bar.

I have one. It tee's into the 7way to get full time 12+ to run a relay. It also has harnesses that tee's into the left and right tail lights to get a signal for tails, turns and reverse.

If they would steal raw voltage from each circuit, the load would be too much, the bcm would freak out and shut the circuit down.

 

[Sanderson1582]

Do use do you use there light bar if you do is that plenty of light for backing up.

 

[gemarsh]

Yes.

 

[Sanderson1582]

Sounds like you’re pretty knowledgeable so you’re happy with the Putco product ? i’ve been searching for fix for the backup light problem on my AT4x Does this product change any of the trailing logic? The light mounts to the truck behind the tailgate and bumper, correct?
Thanks For your help ,

 

[gemarsh]

Going on 3 years without issue. Completely happy with purchase. Bought thru gmc accessories and picked up at my dealer.

Used the included 3m sticky tape on the mounts. I had to remove tailgate. My hands were to big. Multipro tailgate sucks to remove by one's self.

Yes, exactly, mounts to bed right above bumper plastic.

 

[Sanderson1582]

Going on 3 years without issue. Completely happy with purchase. Bought thru gmc accessories and picked up at my dealer.

Used the included 3m sticky tape on the mounts. I had to remove tailgate. My hands were to big. Multipro tailgate sucks to remove by one's self.

Yes, exactly, mounts to bed right above bumper plastic.

View attachment 6444

Thanks again for all your help. I did check the Gmc store and they do offer it .
That makes me feel that better. , the dealer warned me about wiring it up to the truck as far as warranty goes , now that I found Gmc sell the product I should have no worries

 

[skw774]

traded my 2023 for a 2024,kept my light bar only to find out it won't work. GM changed things up from 4 wire to 5 wire so i had to order a new one. anyone out there that wants a deal on one for a 2019 to 2023 holler , it comes with the plug and play harness , you will have to get some 3m tape to attach as all the brackets etc stayed on the trade

 

[Woody_76]

@Sanderson1582 - I purchased the Putco blade for my 2023 AT4 as well, couldn't be happier. Now, it's not as bright as 2 backup lights, but it tucks in nice and neat and isn't hanging down either. I did have my son help me take the tailgate off - it's a 2-person job for sure. As mentioned, it just plugs into both the left and right hand tail lights (as 1/2 of the light bar flashes when the turn signal is on). Probably took about an hour or so since I never did one before, but overall it's plug and play for sure. I tucked all the extra wire into the trailer receiver tube on the driver side (there's plenty of extra wire). Only issue I had was disconnecting the camera - the connector clip snapped... but that's why they make zip ties!

 

[SRacer05]

anyone tried these guys yet?

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