Check trailer lights message

[goat226]

Good evening. I have a new to me 2021 GMC Sierra 1500 at4 with around 39,500 miles. On the dic I'm getting check trailer lights. I  can dismiss the messages but my 7 pin plug does not work. I replaced it  the 2 modules above the spare  tire with no luck fixing it. I was hoping for some help before I take it to the dealer. Thank you in advance and I love this site. 

[newdude]

1 hour ago, goat226 said:

Good evening. I have a new to me 2021 GMC Sierra 1500 at4 with around 39,500 miles. On the dic I'm getting check trailer lights. I  can dismiss the messages but my 7 pin plug does not work. I replaced it  the 2 modules above the spare  tire with no luck fixing it. I was hoping for some help before I take it to the dealer. Thank you in advance and I love this site. 

 

 

Trailer lighting control module failed. 

 

I'm betting you didn't need to replace those two modules you replaced, one likely being the trailer brake control module and the other the chassis control module.    Those two modules won't set "check trailer lights".  The trailer lighting control module does however.  

[goat226]

Thank you for your response but one of the models was the trailer lamp control module and the other was trailer brake control module 

[goat226]

Sorry modules. I'm about at my wits end trying to figure it out 

[64BAwagon]

Have you tried the truck with a different trailer or had someone connect to the trailer thats setting the message ? 

 

What type and vintage of trailer do you have and what type of lighting does it have ? 

 

My understanding is that if the truck doesnt receive the proper feedback from the trailer it will set a fault message. A bad ground on the trailer or a wiring issue can cause these problems. Did you test the 7 way plug on your truck before connecting the trailer ?  

 

Just spitballing some ideas. 

[newdude]

11 hours ago, goat226 said:

Sorry modules. I'm about at my wits end trying to figure it out 

 

 

Did you check the fuses for the lighting control module?  Fuses 46, 63, 74 and 82 in the underhood fuse block.  

 

Also, check your trailer receptacle on the truck for corrosion on the terminals.  

Edited August 8, 2023 by newdude

[EddDe]

Make sure trailer light wiring matches truck. The 7-way trailer light receptacle on our trucks is wired for RV. Some utility trailers use a different 7-way wiring pattern.

[64BAwagon]

A 7 way plug is standardized. I have never seen one any other way unless a replacement was done and it was wired incorrectly. 

[slj2008]

Check your plugs  - Truck & Trailer make sure there clean, Also clean the hitch ball ( Rusted).  Or have a freind try his truck to your trailer .

[Hutchy]

Have you confirmed proper ground? 

[Kastine64]

I have a 2019 chevy silverado LTZ and having the same issues. Taken to 2 different dealerships and all they found was a blown 30 Amp fuse. Something is making it blow. 2nd dealership had my trailer with the truck for a week and couldn't figure it out. After I brought it home, no lights on trailer, a friend tested my plug on my truck and the neg pin was showing a positive charge he reset it and it showed just a negative. All the lights worked on the trailer then. 2 weeks later I hook up trailer and freaking nothing. Trailer works fine on other vehicles so it's not the trailer. Anything I hook to it I get same results. I'm ready to take it back to the dealership. 

[GMCustomerService]

On 9/4/2023 at 3:04 PM, Kastine64 said:

I have a 2019 chevy silverado LTZ and having the same issues. Taken to 2 different dealerships and all they found was a blown 30 Amp fuse. Something is making it blow. 2nd dealership had my trailer with the truck for a week and couldn't figure it out. After I brought it home, no lights on trailer, a friend tested my plug on my truck and the neg pin was showing a positive charge he reset it and it showed just a negative. All the lights worked on the trailer then. 2 weeks later I hook up trailer and freaking nothing. Trailer works fine on other vehicles so it's not the trailer. Anything I hook to it I get same results. I'm ready to take it back to the dealership. 

This is certainly not what we like to hear, Kastine64.  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 2019 Chevrolet Silverado's trailer lights not working properly. To do so, please send an email to [email protected] with ATTN: Kastine64/GM Trucks in the subject line.

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Edited September 14, 2023 by GMCustomerService

[Lone Camper]

On 8/7/2023 at 7:11 PM, goat226 said:

Sorry modules. I'm about at my wits end trying to figure it out 

Hello, I have the same problem. Were you ever able to get this resolved?

 

[heavyGMC]

I was able to resolve the issue to check trailer lights when I was not connected to a trailer by changing 30 AMP fuse #74 TIM. I hope I save you some time.

Edited June 29 by heavyGMC

[Daddy-Butter]

WOW - GMs standards for quality sure have sank over the years. Bad enough my 2021 Sierra X-31 has the upgraded BOSE system in it where the rear speakers barely produce sound even when faded to the rear, GM knows of this flaw and we just have to live with it, but I too have trailer light error messages coming across indicating my left lights are not working and/or the brakes lights on the trailer is not working. This only happens when it is raining out and it doesn't matter if it is with my small cargo/enclosed trailer or my open trailer I get.the same messages. Once there was a code so the dealership set an appointment and then when I brought it in, they said the code automatically clears out if the issue clears out. So it continues to happen and I took photos only to have them tell me unless they can duplicate, there is nothing to be done. This is a serious hazard that can result in an accident if not remedied and my truck is factory equipped with all the towing equipment including the brake controller. This same thing never occurred with my 2019 GMC Canyon that I traded in on this 2021 GMC Siera... All the common denominator is something is wrong with this trucks factory trailer light wiring... What to do???

 

Edited 5 hours ago by Daddy-Butter
Typos fixed and add photo