Jump to content

Trailer lights flashing

plbass
 Share

Recommended Posts

plbass New Member

plbass

Posted
Posted

I have a 2020 GMC Sierra xlt. Whenever I park my boat trailer and turn off truck the trailer LED tail lights flash every 10 seconds. Any ideas on what is causing this?

JJ461 Enthusiast

JJ461

Posted
Posted (edited)

This is normal, it is stated in the owners manual on page 312.

 

"When a trailer is connected and the ignition is off, the Trailering App System will periodically pulse
the lighting circuits of the trailer to verify it is still connected. The trailer lights may periodically flash as a result of this trailer connection detection. These flashes may be more visible in dark ambient light environments. The flashing or flickering lights are a normal condition and the Trailering App System has built-in protections to prevent the battery from draining. When Theft Alert is also enabled
the frequency and pattern of this flashing will change."

Edited by JJ461
  • Like 1
  • Thanks 1
Mudcon Enthusiast

Mudcon

Posted
Posted

Yea mine does it too, it is the truck making sure the trailer is still connected. 

  • Like 1
SVG Enthusiast

SVG

Posted
Posted

Completely normal as stated above. First time I saw it happening I thought WTF??

SVG Enthusiast

SVG

Posted
Posted (edited)
10 hours ago, Chris Callanan said:

I've seen reports of folks with dead batteries in the morning though - so I unplug the trailer overnight just in case :)

I don't have any current facts to back up my position at the moment but I'd be shocked if the trailer monitoring system draws that much power to make a good battery discharge that much.

 

One thing to remember, there is a trailer alarm setting that will set off the alarm if someone disconnects your trailer, presumably in an attempt to steal it.

Edited by SVG
  • Like 2
JJ461 Enthusiast

JJ461

Posted
Posted
On 10/7/2021 at 10:19 AM, SVG said:

I don't have any current facts to back up my position at the moment but I'd be shocked if the trailer monitoring system draws that much power to make a good battery discharge that much.

 

One thing to remember, there is a trailer alarm setting that will set off the alarm if someone disconnects your trailer, presumably in an attempt to steal it.

This is a feature I found out that the truck had at about 10:00 one night when I decided to unplug the trailer after the truck was locked... BTW the key fob was in the house, wasn't popular with the neighbors that night.

  • Like 2
  • Thanks 1
Tmb New Member

Tmb

Posted
Posted

I, too, have this situation with my 2019 Chevrolet Silverado. When my truck is turned off, the trailer lights on my horse trailer continue to flicker repeatedly every 10-15 seconds forever. I’ve resorted to unplugging the trailer to avoid any draw on my battery. 
NEW: I read not to long ago on this forum site that GM had come up with a fix. Some type of new computer module? My Chevy dealership had never heard of it so I had to furnish them the #specs from the Forum article I had read. It’s as yet, not a formal recall. Anyone know any more news on this issue?

SVG Enthusiast

SVG

Posted
Posted

Here is the page from my 2021 owners manual that talks about the trailer sensing. It says there is battery management software to protect the battery from discharging.

 

Maybe earlier year trucks don't have this feature? Not sure.

 

 

2021-gmc-sierra-1500-owners-manual copy.pdf

  • Like 1
Mudcon Enthusiast

Mudcon

Posted
Posted
On 10/7/2021 at 11:19 AM, SVG said:

I don't have any current facts to back up my position at the moment but I'd be shocked if the trailer monitoring system draws that much power to make a good battery discharge that much.

 

One thing to remember, there is a trailer alarm setting that will set off the alarm if someone disconnects your trailer, presumably in an attempt to steal it.

I have left mine plugged in for a week on vacation without cranking my truck at all and did not have a problem with it cranking.  It was nice to have them flash as extra security to let people know or possibly think it might be armed and not try and steal it.  We were riding atvs and from top of the mountain at night I could see my truck flash down where it was parked. Pretty neat. 

  • Like 1
carlosh Enthusiast

carlosh

Posted
Posted
On 10/12/2021 at 1:15 PM, Tmb said:

I, too, have this situation with my 2019 Chevrolet Silverado. When my truck is turned off, the trailer lights on my horse trailer continue to flicker repeatedly every 10-15 seconds forever. I’ve resorted to unplugging the trailer to avoid any draw on my battery. 
NEW: I read not to long ago on this forum site that GM had come up with a fix. Some type of new computer module? My Chevy dealership had never heard of it so I had to furnish them the #specs from the Forum article I had read. It’s as yet, not a formal recall. Anyone know any more news on this issue?

They performed the tsb and plug fix on mine. Now lights only flicker on every 45 minutes or so

Mike_F Enthusiast

Mike_F

Posted
Posted
Quote

They performed the tsb and plug fix on mine. Now lights only flicker on every 45 minutes or so

carlosh

 

Do you have the numbers for the TSB and plug fix.

 

My dealer is clueless or lazy or maybe both, but definitely useless at this point.

 

Thanks

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

  • Latest Articles

  • Posts

    • Atlas
      The Peckish Synapse

      By Atlas · Posted

      There's some truth to the above, but also, she's selling fullsize trucks and bread/butter CUV's like hotcakes, meanwhile, extracting GM's pickups from the deep discounting sales game.   GM's stock has held its own during her tenure, and the more recent buybacks are delivering cash back to investors and signal confidence in their direction forward. Even with the EV losses.   GM is an example of a modern publicly traded company. The #1 goal of any publicly traded company is to deliver the most value possible to shareholders. Despite being a car company, building the best car isn't GM's path to delivering maximum shareholder value.   McDonalds doesn't make the best burger, or the best coffee.   I've mentioned in another thread, I really don't / won't ever understand Cadillac or Buick in a modern context. Both brands are completely dead to me. I'll cede that the Escalade is a nice SUV, but the brand and nameplate mean nothing to me, and GM will never persuade me to pay north of $170k for a gussied-up Tahoe or Burb. Other people don't mind doing that and that's their purview.   The C8 shares absolutely nothing in common with any other current Chevrolet or Corvette on the market. Since its introduction 8 years ago, it's developed quite the following. It did what other Corvettes couldn't do: reduce the average age of its buyer. GM has something there, and I see them investing in the car. They'd better not mess that up.   We've successfully derailed Grumpy's thread again, but I think this one is meant to be more of a random thought thread so a little wandering is probably OK.
    • Tyler Gibbs
      2027 GMC Sierra: Official Discussion

      By Tyler Gibbs · Posted

      Sliding doors ftw   Also, Sienna ftw as well.  The in-laws got a 2024-2025 recently when their 2019 sienna was totaled due to a deer back in June.  They've been getting 38-40mpg on the 65mph highway they live on.
    • xdieselmechanic
      07 yukon xl 6.2 stalls at hot idle and wont restart

      By xdieselmechanic · Posted

      Forgot to mention that this started after changing the oil I use mobile 1 full syn with mobile one filter but I did add pro lube additive and was the first time doing so and is making me wonder just can't see why that would matter
    • xdieselmechanic
      07 yukon xl 6.2 stalls at hot idle and wont restart

      By xdieselmechanic · Posted

      I apologize for long post put going to try to explain everything. Parts replaced so far: Cam sensor Crank sensor Cam phaser valve Cam phaser solenoid Fuel pump Maf 1 injector Pcm Pdm   So about 2 weeks ago coming off the highway my 2007 yukon xl with the 6.2 stalled and would restart. Had unit towed back to house and I messed around with relays and unit started. Drove it the next day and same thing. Had it towed again. Scanned unit and had code p0300 with misfire data showing mainly cylinder 7 but I know that won't cause a no start. Measure fuel pressure and found only 42 psi replaced pump to have unit stall again and not restart. This time I stayed on back roads and just waited for it to restart about 30 to 60 min. During this time I found I have no injector pulse but have good power at injectors. Started unplugging 1 injector at a time and found when unplugging cylinder 7 pulse came back so i changed injecto and same issue. Turns out unit just happen to ready to start at that time. Scanned into unit and found no reason for the pcm to take away injector pulse so I replaced the pcm and same issue. I figured timing sesnor controlled the injector pulse so I replaced both sensors and while I had the water pump of i replaced the vvt components while i was in there. Read multiple people have luck chaging the maf for this issue so I changed it. Unit still stalls to this day and loses injector pulse on the ground side when it does. Have noticed watching the live data the pcm is request injectors to fire via injector pwm value. I have redone the ground wires at the left bottom of the block knowing this was the ground location for the pcm but still no luck. I am a mechanic by trade but this is having me pull my hair out. If anyone has something to have me check I will gladly im not much of a parts thrower but im about to load the cannon
    • newdude
      auto mechanical driver's door unlock without pressing button? [2026 Silv. 1500 WT 4WD RC SB 2.7L]

      By newdude · Posted

      Actually.  Wait.   I just re-read your original post.  Are you talking from INSIDE the truck you have to hit unlock?  Or from the key fob?  I had assumed from the key fob.   IF you are talking the inside unlock button, I assume you are shifting to park and its not unlocking the doors?  If so, that is changed via the settings page in the radio.  Go to SETTINGS, then VEHICLE and then it should be under LOCKS or DOOR LOCKS or something like that.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...