21-NA-155
Service Bulletin Details
Public Details for: 21-NA-155
This informational bulletin advises the technician to check for faults that may be caused by the trailer otherwise found by a possible faulty trailer connector.
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Models from 2024
Models from 2023
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2020 CHEVROLET SILVERADO 1500 |
2020 CHEVROLET SILVERADO 2500 |
2020 CHEVROLET SILVERADO 3500 |
2020 GMC SIERRA 1500 |
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Models from 2019
2019 CHEVROLET SILVERADO 1500 |
2019 GMC SIERRA 1500 |
Bulletin No.: Service Bulletin Date: 21-NA-155 January, 2024 INFORMATION Subject: Information on Check Trailer Wiring Message and/or Service Trailer Brake Displayed on Driver Information Center (DIC) - DTC C1114 Set Brand: Model: Cadillac to Escalade Models 2021 2024 Silverado 1500 (New Model) 2019 2019 Silverado 1500 2020 2021 2022 2022 Silverado 1500 2023 2024 Silverado 2500HD/ 3500HD 2020 2024 2021 2024 Sierra 1500 (New Model) 2019 2019 Sierra 1500 2020 2021 2022 2022 Sierra 1500 2023 2024 Sierra 2500HD/ 3500HD 2020 2024 Yukon Models 2021 2024 Silverado 1500 - LTD (RPO J21, VIN Digit 5 = W / Y) Chevrolet Silverado 1500 - New (RPO J22, VIN Digit 5 = A / D) Suburban Tahoe Sierra 1500 - Limited (RPO J21, VIN Digit 5 = 8 / 9) GMC Model Year: from Sierra 1500 - New (RPO J22, VIN Digit 5 = H / U) VIN: from to Engine: Transmission: Involved Region or Country North America, Middle East, Chile (West), Thailand (ASEAN), Paraguay Additional Options (RPOs) JL1 (CONTROL-INTEGRATED TRAILER BRAKE) Condition Some customers may comment on one or more of the following messages displayed on the DIC: • Check Trailer Wiring • Service Trailer Brake Some technicians may find DTC C1114 set on vehicles equipped with an Integrated Trailer Brake Controller. Copyright 2024 General Motors LLC. All Rights Reserved. Page 2 January, 2024 Bulletin No.: 21-NA-155 Note: The below two possible causes can also affect a truck equipped with an aftermarket trailer brake controller Cause This condition may be caused by a poor connection at the 7-way trailer connector at the vehicle and/or trailer side of the connector. – Trailer Side Connector (Plug) - There are several manufacturers of 7-way (trailer side) connectors and many do not comply with the SAE standard specifications. Some 7-way (trailer side) connector plugs may not properly engage the truck's 7-way connector socket and cause open circuits. Since the Trailer Brake Control Module is always monitoring the vehicle and trailer circuits/components, a poor connection at the 7-way connector can cause a “Check Trailer Wiring” message on the DIC. This may also cause deformation and excessive wear of the terminals on the truck's 7-way connector socket. Over time, this will lead to poor terminal tension between the 7-way (trailer side) connector plug and the truck's 7-way connector socket. 7-Way Trailer Connector: – The 7-Way Trailer Side Connector (Plug) - 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 two connectors are mated. Pollak's website is: www.pollakaftermarket.com. Once at the home page select "Connectors" then "Heavy Duty 7-Way Plugs and Accessories" and then " RV Connectors Heavy Duty & Adaptors" (example 12-706, 12-702). Note: If the truck's 7-way connector socket terminals are deformed or have excessive wear, it will be necessary to replace the truck side connector, see info below, along with the trailer's 7-way connector plug to a Pollak HD. Information • Truck Side Connector (Socket) - If the truck's 7-way trailer connector socket terminals are deformed, have excessive wear, door/cover not holding trailer connector plug securely, etc. it will be necessary to replace the truck side trailer connector socket with updated GM part number 84056018. Trailer Side Customer Recommendation: 1. Inspect and clean the ground wire (normally white wire) connection on the trailer side of the 7-pin connector. 2. Make sure that the wires inside the trailer side connector are clean and securely fastened. 3. If an electrical junction box exists on the trailer, make sure the wires inside the junction box are clean and securely fastened. 4. Inspect Trailer Grounds for potential issues. Note: Trailer System issues should not be covered under the GM Bumper-to-bumper warranty. Customer Trailer Recommendation: Refer to bulletin : Information On Common Customer Trailer Side Faults to print the procedure that can be used to help the customer understand any trailer related issues. Note: Trailer side system issues should not be covered under the GM Bumper-to-bumper warranty. Important: Service agents must comply with all International, Federal, State, Provincial, and/or Local laws applicable to the activities it performs under this bulletin, including but not limited to handling, deploying, preparing, classifying, packaging, marking, labeling, and shipping dangerous goods. In the event of a conflict between the procedures set forth in this bulletin and the laws that apply to your dealership, you must follow those applicable laws. Bulletin No.: 21-NA-155 January, 2024 Page 3 The Following Failures are the Result of Trailer Side Connection Issues - Non Warranty Issue ⇒ When diagnosing trailer message issues without the trailer present, please refer to Document ID: 5627183: PIT5509G: Diagnostic Tip - Check and/or Service Trailer Brake System message DTC C1114 The Following failures are the result of trailer side connection issues: 5867995 3. Trailer side connector is damaged/deformed causing removal of protective plating. This is the result of the trailer side connector is moving or bouncing when connected (excessively worn connector) – Non-Warranty Issue. 5867917 1. Short on trailer side damaged the terminal – Trailer side connector is loose/worn – Non-Warranty Issue. 5867997 4. Trailer side harness retention tab has been broken off cover which is the result of customer pulling away from trailer without releasing the trailer harness – Non-Warranty Issue. 5867994 2. The blue/green is expected, and this small amount of corrosion does not impact function of connector – Non-Warranty Issue. Page 4 January, 2024 The Following Failures are the Result of Vehicle Side Connection Issues Subject to Terms of Warranty Bulletin No.: 21-NA-155 Parts Information Causal Part N/A Description 84056018 Part Number Truck 7-way Trailer Connector Socket Qty 1 Warranty Information For trailer related issues: No warranty labor operation is provided for concerns related to the trailer. For Truck 7-Way Connector Replacement use: For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the following labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for coverage information. 5867998 1. Sealant from part on terminals, would cause intermittent connection issues connecting to trailer – Subject to terms of warranty. 5868000 2. Terminal is pushed out – Subject to terms of warranty. Labor Operation Description Labor Time 5486198* Tow Vehicle Electrical Receptacle Diagnostic 0.3 hr Add Tow Vehicle Electrical Receptacle Replacement 0.2 hr *This is a unique Labor Operation for Bulletin use only. Bulletin No.: 21-NA-155 January, 2024 Page 5 Version 3 Modified Released September 21, 2021 Revised June 14, 2022 - Added 2022 to Model Year and Updated Information section. Revised January 11, 2024 - Added the 2023 — 2024 Model Years. GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION