Trailer lights not shutting on 2020 Trail Boss

[Terry Reeves]

My 2020 Trail Boss has had issues with trailer errors since it was new. Now it keeps displaying check trailer lights while the running lights never shut off on the trailer. (both my trailers).

Dealer says there is short somewhere. I am not so sure. It appears to be a problem with the trailer module. 

[EddDe]

I was randomly seeing the notice to check trailer wiring on my 2020 LT when towing travel trailer, but trailer brakes and lights were working normally. Dealership found stored code C1114 (no MIL) and gave me this TSB. I bought the Pollak 12-706 trailer plug from Amazon and have not seen notice since, despite the Pollak plug being thin plastic. Good luck.

 

TSB 21-NA-155, Date: June 2022

https://static.nhtsa.gov/odi/tsbs/2022/MC-10214860-0001.pdf

 

Subject: Information on Check Trailer Wiring Message and/or Service Trailer Brake Displayed on Driver Information Center (DIC) - DTC C1114 Set

 

Engineering has recommended the use of

Pollak Heavy Duty 7-Way (Trailer Side) Connector Plugs. Pollak is the OEM

manufacturer of the truck's 7-way connector socket; and by using a Pollak Heavy Duty 7-Way (Trailer Side) Connector Plug, this will ensure proper fit when the twoc onnectors are mated... (example 12-706, 12-702).

 

[gemarsh]

On 9/20/2023 at 9:46 PM, Terry Reeves said:

My 2020 Trail Boss has had issues with trailer errors since it was new. Now it keeps displaying check trailer lights while the running lights never shut off on the trailer. (both my trailers).

Dealer says there is short somewhere. I am not so sure. It appears to be a problem with the trailer module. 

 

There was a discussion on the HD forum 1st week of September. This was the fault.

 

 

https://www.gm-trucks.com/forums/topic/264353-solved-12v-battery-feed-circuit-seems-to-be-tied-to-the-tail-lamps-circuit/