Trailer lights

[Landcrusher]

I have a 2020 High Country Duramax 

none of the connectors on the vehicle

work. 
I have tested the lights on the trailers and they work great. 
If I plug in my tester for the flat four pin all I get is a light flash from the two turn signal poles. 
I am trying to connect sled deck and the connectors in the box and on the bumper do not work at all. 

[TripDad]

Just retrieved my 2020 AT4 2500HD from the local GMC service center.  My trailer will connect, but then disconnects and reconnects intermittently.

 

I was told everything is working as designed, and my problem is the LED lights.  I did try the Curt product mentioned above to no avail.  This is my second camper that this happened on.

 

This truck is my first and last GM product.

 

I am working on a workaround.  If I am successful I will post back.  Aside from this issue, and this is a big issue for me, I like the truck.

Edited January 28, 2020 by TripDad
added content

[Cool J]

I just returned from a trip to south Texas and found that you need to shut off your truck before connecting and disconnecting your trailer plug. Everything has been working since.

[Wbrisett]

On 1/28/2020 at 6:11 PM, Cool J said:

I just returned from a trip to south Texas and found that you need to shut off your truck before connecting and disconnecting your trailer plug. Everything has been working since.

I have a loaner 2020 1500 while my 2020 2500 is in the shop. I have found the same, but with all the electronics in it, it kind of makes sense. 

[yousaveone]

You need this

https://www.shopchevyparts.com/trailering/2020-silverado-1500-trailer-electrical-adapter-way-blade-way-flat/19366958-p-92306593.html

[SkidooSteve12]

14 hours ago, yousaveone said:

You need this

https://www.shopchevyparts.com/trailering/2020-silverado-1500-trailer-electrical-adapter-way-blade-way-flat/19366958-p-92306593.html

If you need that adapter, that would be sad that the provided built in 4 way plug can't be used.

I already had to buy a 4 way plug wire extension because the built in plug is so high above the hitch now compared to my last Silverado.

[yousaveone]

I can't find the flat 4 on my 2020, did they remove it? Where is yours at?

[Garett Dixon]

My 20120 1500 does not have a four flat because it has the rear trailer camera plugs. So it only has the 7 way and two trailer camera connections. 

[yousaveone]

That's what mine has too. Look like we need the GM adapter, its only $14 so whatever.

[SkidooSteve12]

My 4 way plug is right above the 7 way plug, but I don't have the upgraded trailer camera package.

[mkeddie]

Anyone with the trailer camera package and fifth wheel connection in the box know if they are able to be swapped
Would like the 4 pin on the bumper

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[Cool J]

The video cables are not long enough to move the plug from the bumper into the bed. I would suspect that someone will develop a way to adapt in the near future.

[Mott]

I have a 2020 At4 2500.  First time I started towing my boat trailer it was all good.  Set up my profile in app was easy.  Now last week, went to pull the boat and message came up recalled brake gain.   Diagram of diagnosis showed prong was not connecting in plug so was causing my trailer electric brakes on passenger side to stick.  Called dealer and they said my module was bad, ordered and replaced.   Went to tow boat yesterday and same message came up along with no trailer connected.  To see if it was my trailer hooked up to some friends trailers.  Still, the same with no trailer connected.   At this point, I’m very frustrated but will try dealer again today.

[Jav_eee]

I have a 2020 At4 2500.  First time I started towing my boat trailer it was all good.  Set up my profile in app was easy.  Now last week, went to pull the boat and message came up recalled brake gain.   Diagram of diagnosis showed prong was not connecting in plug so was causing my trailer electric brakes on passenger side to stick.  Called dealer and they said my module was bad, ordered and replaced.   Went to tow boat yesterday and same message came up along with no trailer connected.  To see if it was my trailer hooked up to some friends trailers.  Still, the same with no trailer connected.   At this point, I’m very frustrated but will try dealer again today.

You’re saying it’s not normal for the trailer profile to recall the brake gain setting for that specific trailer?


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[mx_master]

For those that have sled decks this worked very well bought a two prong plug from amazon and wired into the taillight then plug the deck into it. This makes a nice looking install but also easy to remove the deck.