Jump to content

Trailer Light Control

Hardhands85
 Share

Recommended Posts

Hardhands85 New Member

Hardhands85

Posted
Posted

I drive a 2021 Chevy 2500hd. Having an issue with trailer lights staying on. Is there a trailer light control module on my truck? The dealership is telling me no. But everything else I see online it says there is one. Does anyone know which module controls the trailer lights on this truck? Vin 1GB1YLE73MF171983

davester Senior Enthusiast

davester

Posted
Posted (edited)

What do you mean by "staying on"?  They are fully on, after turning off the truck and the trucks lights are off?  All the time, even the truck is running and the truck's lights are off? Or something else?

Edited by davester
Hardhands85 New Member

Hardhands85

Posted
  • Author
Posted
11 hours ago, chris21 said:

Check the ground on the trailer

Ground is good. It does it on ever trailer I hook to. With the truck shut off the passenger side running lights and tail lights stay on no matter if the truck running or not. Getting 12v at truck plug 100% of the time .

newdude Senior Enthusiast

newdude

Posted
Posted (edited)
17 hours ago, Hardhands85 said:

I drive a 2021 Chevy 2500hd. Having an issue with trailer lights staying on. Is there a trailer light control module on my truck? The dealership is telling me no. But everything else I see online it says there is one. Does anyone know which module controls the trailer lights on this truck? Vin 1GB1YLE73MF171983

 

 

You do NOT because you have the WT trim and ZW9 box delete. 

 

All trailer lighting is handled via the relays and fuses in the under hood fuse box.  Fuses 41, 55, 63, 73 and 81. 

 

Do you have any sort of aftermarket box, dump, body of some sort installed on this?

 

Edited by newdude
  • Like 1
asilverblazer Senior Enthusiast

asilverblazer

Posted
Posted
4 hours ago, Hardhands85 said:

...the passenger side running lights and tail lights stay on no matter if the truck running or not. Getting 12v at truck plug 100% of the time.

There is not a specific running/tail light for the passenger side.

 

The only light specific to a side is turn signal (technically this includes brake lights too).

 

When you say that you are getting 12v at the truck plug 100% of the time, I'm assuming that you are probing the pin labeled "Right Turn". 

 

The only circuit that carries 12v to the trailer is the auxiliary power circuit used to charge trailer 'house' batteries or break away back-up batteries. It sounds like this circuit is somehow powering the right turn pin - whether by intention (maybe a previous owner changed the truck for some reason?) or by mistake.

 

Long story truck I would first confirm that all circuits going to the trailer plug are in the correct spot. gmupfitter.org will have wiring diagram and colors for the truck you can use to confirm.

chris21 Enthusiast

chris21

Posted
Posted (edited)
On 3/17/2026 at 7:37 AM, Hardhands85 said:

Ground is good. It does it on ever trailer I hook to. With the truck shut off the passenger side running lights and tail lights stay on no matter if the truck running or not. Getting 12v at truck plug 100% of the time .

 Sounds like connector on the truck is not wired correctly

Edited by chris21

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.3k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,739
    Total Members
    8,960
    Most Online
    chfkief
    Newest Member
    chfkief
    Joined

  • Who's Online   3 Members, 0 Anonymous, 1,450 Guests (See full list)

  • Latest Articles

  • Posts

    • Chuck FB
      Joke Thread

      By Chuck FB · Posted

      Fred was in the fertilized egg business. He had several hundred young pullets, and ten roosters to fertilize the eggs He kept records, and any rooster not performing went into the soup pot and was replaced. This took a lot of time, so he bought some tiny bells and attached them to his roosters. Each bell had a different tone, so he could tell from a distance, which rooster was performing. Now, he could sit on the porch and fill out an efficiency report by just listening to the bells. Fred's favourite rooster, old Butch, was a very fine specimen, but this morning he noticed old Butch's bell hadn't rung at all! When he went to investigate, he saw the other roosters were busy chasing pullets, bells-a-ringing, but the pullets, hearing the roosters coming, would run for cover. To Fred's amazement, old Butch had his bell in his beak, so it couldn't ring. He'd sneak up on a pullet, do his job and walk on to the next one. Fred was so proud of old Butch, he entered him in the City Show and he became an overnight sensation among the judges. The result was the judges not only awarded old Butch the "No Bell Piece Prize," but they also awarded him the "Pulletsurprise" as well. Clearly old Butch was a politician in the making. Who else but a politician could figure out how to win two of the most coveted awards on our planet by being the best at sneaking up on the unsuspecting populace and screwing them when they weren't paying attention. Vote carefully in the next election, you can't always hear the bells.
    • chfkief
      FS: Black Bear Performance AutoCal Tuning System

      By chfkief · Posted

      Do you still have?
    • 3CarSeatDad
      High Country Suburban build confirmation

      By 3CarSeatDad · Posted

      Can someone confirm if the GM order workbench terminal is able to validate a custom build sequence:   1) Initialize the Allocation Base: Open a new vehicle build queue, select the 2026 Chevrolet Suburban 4WD, and pick the High Country (3LZ Preferred Equipment Group).   2) Select the Diesel Powertrain: Go directly to the engine configuration screen and choose RPO code LZ0 (3.0L Duramax Turbo-Diesel). Ensure it maps to the MHS 10-speed automatic transmission.   3) Deploy the Seating Swap: Navigate to the Interior Options screen and enter RPO code ATT to replace the standard captain's chairs with the power-release 60/40 bench seat. Because you are not trying to force a separate luxury or air-suspension bundle, the standard, premium D07 Fixed Floor Console remains active. The system will accept this change immediately without triggering a warning message.   3)Apply Heavy-Duty Hauling Capability: Input RPO code NHT (Max Trailering Package). The commercial terminal will automatically bundle the required trailering hardware and software modules to support the diesel engine's maximum towing capacity.   5) Layer the Premium Tech and Glass: Separately add code C3U (Panoramic Power Sunroof) and code UKL (Super Cruise) to the order screen.   6) Run the Final Validation: Click the "Validate Order" button at the bottom of the interface.
    • revmanii
      Looking at ordering a '26 WT because I want a std cab, std bed

      By revmanii · Posted

      Spent the last hour or 2 googling and reading up on the spacer thing. I don't like the loss of thread contact on the slip on spacers, but it appears you can get "extended" lug nuts that reach into the hole of the wheel to get back the lost threads. Looks like the only true hubcentric slip on spacers are at least .375". I'd want as little as I could get away with and don't want to cause other clearance issues going any thicker. Bora seems to offer what appears to be a well made .375" spacer and extended lug nuts. I searched here and did find a couple threads recommending Bora. But not cheap. By the time I buy spacers and lugs, new TPMS sensors, then pay a tire shop to install the new sensors, I suspect I'm going to be in over $400. Thinking about running out and getting some washers to put behind the wheel to see if .375" is enough to clear calipers, turn lock to lock without rubbing, and to see if the wheels/tires look strange pushed out a little. This would just be to check fitment.
    • Core-Lokt
      Road Master Active Suspension

      By Core-Lokt · Posted

      Roadmaster makes some quality parts; I have their sway bar. I considered the RAS, but I ended up bagging. I didn't know what kind of ride I'd get with RAS, and the bags have interior jounce bumpers, so I can run 0 pounds pressure. I figured I'd have the best of normal suspension ride with assist on-demand. But it seems you got pretty much the same in one item.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...