7-way plug issues

Shawn O'Leary · January 16, 2022

Hi Guys:

Bought an Airstream to tow behind my 2019 GMC Sierra Denali (added a leaf spring package and the Brembo brake upgrade to assist with it, but that's another topic). Anyway, the truck doesn't recognize the trailer nor any tester units. Only the 12v power works; none of the signals/lights (rechecked with a multimeter and the same). I've checked the connections and grounds and as far as I can tell everything is fine. I've checked it both with tow/haul on and off; same deal.

Before I throw my hands up and make an appointment with the dealer is there anything obvious I'm missing? Thanks!

RocksRock · January 16, 2022

20 minutes ago, Shawn O'Leary said:

Hi Guys:

Bought an Airstream to tow behind my 2019 GMC Sierra Denali (added a leaf spring package and the Brembo brake upgrade to assist with it, but that's another topic). Anyway, the truck doesn't recognize the trailer nor any tester units. Only the 12v power works; none of the signals/lights (rechecked with a multimeter and the same). I've checked the connections and grounds and as far as I can tell everything is fine. I've checked it both with tow/haul on and off; same deal.

Before I throw my hands up and make an appointment with the dealer is there anything obvious I'm missing? Thanks!

Hi Shawn:

I pull a large equip trailer. It was plug and play, no problems.

I used to pull a 26’ Passport. I would check fuses on RV and truck first.
If all good there, then dealer.
Hope this helps.

Shawn O'Leary · January 16, 2022

7 minutes ago, RocksRock said:

Hi Shawn:

I pull a large equip trailer. It was plug and play, no problems.

I used to pull a 26’ Passport. I would check fuses on RV and truck first.
If all good there, then dealer.
Hope this helps.

Didn't think of the fusebox (slapping my forehead). Will check that next before taking it in.

slj2008 · January 16, 2022

Why didn't Airstream check them out when you hook up ?? ON my 2015 the cables were laying by the Fuse Box ( under hood ) one for 12volts power , and the other for all your lights . CHECK your main Fuse box under hood.

Transient · January 16, 2022

Does the Airstream have LED lights?

RocksRock · January 16, 2022

I agree, Airstream should have checked the plug/lights/brakes.

Shawn O'Leary · January 16, 2022

They did, it's the truck not the trailer. Fuses are present and all good. Going to the dealer Tuesday.

EddDe · January 17, 2022

12 hours ago, Shawn O'Leary said:

Hi Guys:

Bought an Airstream to tow behind my 2019 GMC Sierra Denali (added a leaf spring package and the Brembo brake upgrade to assist with it, but that's another topic). Anyway, the truck doesn't recognize the trailer nor any tester units. Only the 12v power works; none of the signals/lights (rechecked with a multimeter and the same). I've checked the connections and grounds and as far as I can tell everything is fine. I've checked it both with tow/haul on and off; same deal.

Before I throw my hands up and make an appointment with the dealer is there anything obvious I'm missing? Thanks!

Download TSB 20NA198 at this link. There is a problem with 2019 models where light circuit will overload if too many incandescent bulbs are on a trailer. Issue was changed on 2020 models to allow more amps.

https://www.carcomplaints.com/Chevrolet/Silverado_2500/2020/tsbs/tsb-20na198.shtml

Dmax3 · January 21, 2022

I've gotten "no trailer connected" notice a few times. The truck receptacle does move in the mount, but the dealer told me it's normal and they couldn't replicate my issue. I'll double check my trailer wiring, but pretty sure it's the truck, not the trailer.

LSMAN · January 23, 2022

I have an Airstream as well. (On my 4th one). When I purchased my truck remotely in march 2020 and the dealer delivered it (2020 RST) , There was no brake controller for towing. I made it very clear that I have an airstream and the sales guy apologized for mistake. His boss allowed him to purchase an aftermarket controller for me. it was ordered and sent to me- I installed it. Looks factory. (I installed something similar an aftermarket controller in my 06 Silverado for my 1966 Airstream)

Sorry if I missed the obvious here but does your truck have a factory brake controller? If not you need one. If it does have a controller her is what I would do:

Check the grounds on both the trailer and the truck. Bad Grounds cause most problems. With trailer unhooked from truck use a 12 volt battery and power up the trailer lights individually: running lights, brake lights electric brakes. Verify that the problem is not on the trailer side first. make sure that you do not power up the emergency brake pull. If engage for long period powering this will burn up that (plunger switch with cable.) LED lights will not cause the above problem.