No power to trailer lights

Mark Gilkes · May 23, 2022

Good morning. I have a brand new 2022 Rockwood trailer and I get no running lights (no power to my backup camera either) when I hook up my 2019 AT4. If I manually turn on the head lights, the running lights now will work. Sounds like I need to go to the dealer with this issue and get nowhere like the rest you, right?

Anacortes Army Guy · May 23, 2022

4 minutes ago, Mark Gilkes said:

Good morning. I have a brand new 2022 Rockwood trailer and I get no running lights (no power to my backup camera either) when I hook up my 2019 AT4. If I manually turn on the head lights, the running lights now will work. Sounds like I need to go to the dealer with this issue and get nowhere like the rest you, right?

Have you used your truck to tow another trailer with it powering up its lights properly? If not, I'd recommend hooking up to another trailer to determine if it's a truck or trailer issue. The RV seller should be more than willing to let you connect to one of their other trailers. Finally, does your AT4 have the tow package that provides the trailer light test option? If so, when you select the "Connections" option does it state that everything is "good to go?"

Mark Gilkes · May 23, 2022

Thanks for the reply. I have a small utility trailer and everything works fine with that. As soon as I turn my headlights from "auto" to "on" in the truck the running lights on the brand new camping trailer work fine. Yes, it has a light testing cycle and I get no errors from that.

Toomas · June 3, 2022

I have same problem with lights no working on 2020 2500hd with an additional problem, I get error messages to check left signal, then right signal, then brake lights and no trailer is attached. Working fine until last time I hooked up trailer, also when this happened my turn signals blink really fast

GMCustomerService · June 9, 2022

On 6/3/2022 at 6:36 PM, Toomas said:

I have same problem with lights no working on 2020 2500hd with an additional problem, I get error messages to check left signal, then right signal, then brake lights and no trailer is attached. Working fine until last time I hooked up trailer, also when this happened my turn signals blink really fast

This is certainly not what we like to hear, Toomas. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2020 2500hd. To do so, please send an email to [email protected] with ATTN: Toomas/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s privacy policy, please visit https://www.gm.com/privacy-statement.html.

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TA^Guy · July 3, 2022

My turn...

I’ve been towing this camper since I purchased my truck new almost two years ago, before that I pulled it with my 2015 Sierra. I've never had a problem until last week. Pick up my camper, checked the lights and everything worked fine. I get to the campground and notice the running lights were on w the truck off and a slight strobe effect from the tail lights. Then I check my brake and turn signal lights. Nothing. My truck also doesn’t see a trailer connected.

My buddy hooked up his Titan and everything worked fine. Used a test light on my truck's 7 pin and it shows only running lights and constant power have current.

I brought it to the dealer, they tested it and sent me a video, everything works for them but they did replace the receptacle for me. I take the truck back to my trailer, still same results. A few weeks ago I did pull my small cargo trailer and had no problems. Both trailers have LED lights, tomorrow I'll go to my camper and check the ground circuit if I can.

Wish me luck and please post any help you might have.

TA^Guy · July 4, 2022

My turn...

I’ve been towing this camper since I purchased my truck new almost two years ago, before that I pulled it with my 2015 Sierra. I've never had a problem until last week. Pick up my camper, checked the lights and everything worked fine. I get to the campground and notice the running lights were on w the truck off and a slight strobe effect from the tail lights. Then I check my brake and turn signal lights. Nothing. My truck also doesn’t see a trailer connected.

My buddy hooked up his Titan and everything worked fine. Used a test light on my truck's 7 pin and it shows only running lights and constant power have current.

I brought it to the dealer, they tested it and sent me a video, everything works for them but they did replace the receptacle for me. I take the truck back to my trailer, still same results. A few weeks ago I did pull my small cargo trailer and had no problems. Both trailers have LED lights, tomorrow I'll go to my camper and check the ground circuit if I can.

Wish me luck and please post any help you might have.

Fast325it · July 30, 2022

Has anyone found a fix?? The trailer lights on all of my trailers worked just fine on my 2019 Silverado; 4 plug snowmobile trialer, 7 plug enclosed trailer, 7 plug skid steer trailer. Today with my skid steer trailer connected, the running lights don't work. Brake and turn signals work just fine. I connected to my 4Runner to the trailer and the lights work just fine. So, I traied connecting the Silverado to a little 4 plug trailer and an enclosed 7 plug trailer and none of the lights work. The truck indicates that there is no trailer connected. The lights on all of the trailers work just fine on the 4Runner and I used all of the trailers recently with the Silverado and they all worked. So frustrating... I love the SIlverado but it's not practical to have a 4Runner around just to tow trailers. All of the fuses are good. Anyone??

davester · July 30, 2022

3 hours ago, Fast325it said:

Has anyone found a fix?? The trailer lights on all of my trailers worked just fine on my 2019 Silverado; 4 plug snowmobile trialer, 7 plug enclosed trailer, 7 plug skid steer trailer. Today with my skid steer trailer connected, the running lights don't work. Brake and turn signals work just fine. I connected to my 4Runner to the trailer and the lights work just fine. So, I traied connecting the Silverado to a little 4 plug trailer and an enclosed 7 plug trailer and none of the lights work. The truck indicates that there is no trailer connected. The lights on all of the trailers work just fine on the 4Runner and I used all of the trailers recently with the Silverado and they all worked. So frustrating... I love the SIlverado but it's not practical to have a 4Runner around just to tow trailers. All of the fuses are good. Anyone??

It's not clear what truck you are referring to, that's not working with your trailers. You started with your '19 Silverado, and said they all worked fine with that truck, then to "the Silverado", where they didn't work, and then the 4Runner, where they did work.

So were you referring to the '19 Silverado, or the '07 Silverado in your profile info?

TrentA · August 22, 2022

My running lights on a 2021 Silverado do not work with a brand new trailer. When I do the test feature on the truck they do though. So, I am completely confused that they will work when I do the test feature on the truck, but wont work afterwards. Blinkers and brake lights will work when pulling the trailer, but not running lights.

Edited August 22, 2022 by TrentA

davester · August 23, 2022

From other reports, it's possible your trailer lights are all LED and use so little power the truck decides they aren't working and doesn't power them. You might try adding some resistors to make the parking lights use more power, or switch them to incandescents. Resistors would be my choice, but I don't know what the value/rating should be for your trailer.

It might also be something else...

Edited August 23, 2022 by davester

GMCustomerService · August 26, 2022

On 8/22/2022 at 12:50 AM, TrentA said:

My running lights on a 2021 Silverado do not work with a brand new trailer. When I do the test feature on the truck they do though. So, I am completely confused that they will work when I do the test feature on the truck, but wont work afterwards. Blinkers and brake lights will work when pulling the trailer, but not running lights.

This is certainly not what we like to hear, TrentA. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2021 Silverado. To do so, please send an email to [email protected] with ATTN: TrentA/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s privacy policy, please visit https://www.gm.com/privacy-statement.html.

Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
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Hunter Dale · August 29, 2022

I recently purchased my 2022 GMC 1500 and I am having the same issue. My truck will not pick up my utility or boat trailer. I had the dealership check it out for me and they just said there wasn't anything wrong with the truck. Something is defiantly wrong with the truck though! I can hook my Jeep up to the boat or utility trailer without issue. Very frustrating!

GMCustomerService · September 2, 2022

On 8/29/2022 at 2:39 PM, Hunter Dale said:

I recently purchased my 2022 GMC 1500 and I am having the same issue. My truck will not pick up my utility or boat trailer. I had the dealership check it out for me and they just said there wasn't anything wrong with the truck. Something is defiantly wrong with the truck though! I can hook my Jeep up to the boat or utility trailer without issue. Very frustrating!

This is certainly not what we like to hear, Hunter Dale. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2022 GMC 1500. To do so, please send an email to [email protected] with ATTN: Hunter Dale/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s privacy policy, please visit https://www.gm.com/privacy-statement.html.

Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
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Virgil Lee · September 4, 2022

On 8/29/2022 at 2:39 PM, Hunter Dale said:

I recently purchased my 2022 GMC 1500 and I am having the same issue. My truck will not pick up my utility or boat trailer. I had the dealership check it out for me and they just said there wasn't anything wrong with the truck. Something is defiantly wrong with the truck though! I can hook my Jeep up to the boat or utility trailer without issue. Very frustrating!

Hey there Hunter Dale, and yes it can be very frustrating with the trailer tail light issue. I hope you have better luck with GM customer service than I did, they say that they want to help, but have a defined script they follow, and zero knowledge of what your problem really is. I'll bet that when you went to the dealer, they hooked it up to a Trailer Simulator and said it is working per design. HaHa, the design is flawed, the simulator only tests within the narrow current band that their system will recognize that a trailer is plugged in; there is an earlier GM TSB that actually has some steps to check and replace trailer light control module, before it got superceded by the latest revision to the TSB, which just uses simulator to simulate a trailer as a way to save money and not fix your truck. The dealer can go no further with any warranty fix, as long as it passes the trailer simulator test. FYI, my truck passed that simulator test three times, before it eventually failed the simulator test and they had to replace the Trailer Lighting Control Module, actually replaced it twice because the 1st one was also faulty. It was a nine month saga for me, with alot of frustration and calls, before eventually someone from the executive leadership team was assigned and assisted with getting the faulty module replaced. There is a relay in that module that will not pass power onto your tail lights, unless it senses a trailer is plugged in, the current band it needs to see on your trailer to turn on your tail lights is outside the range of many of the trailers on the market. In my case, I had 5 different trailers, counting the two boats and non of them had working tail lights when plugged into my 2020 3500 LTZ, all of them worked on my 2015 2500 LT. The 4 wire plug trailers worked fine on my wife's 2019 GMC Arcadia, yet GM "Customer Service" kept telling me that the truck wiring was fine and my trailers were not compatible with the new truck. Trips to the boat launch before the replacement, were more nerve wrecking with no tail lights before dawn. After the fix, the three 7 wire plug trailers work fine, I had to purchase a 7 wire to 4 wire adapter with extra resisters for the boat trailer tail lights to work. Did you know that the folks you call for GM customers service, including their supervisors are not GM employees, contract company is now used. I will give you $100, if you can find a phone number/contact for a GM Regional Customer Service Manager/VP that can help you. Best of Luck to You, I expected much better service and follow-up, from the GM that I was previously accustomed to. Now, my dilemma, is that they finally started the build on the Ford F-350, supercab, LWB, 4wd that I ordered, as I was not going keep the GM if the trailer lights couldn't get fixed, but I do like the Duramax/Allison drivetrain quite a bit, however, I believe the best way to let a company know you feel is with your wallet???