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GM Releases Fix For GMC Sierra, Yukon And Hummer EV Trailer Brake Control Switch Issue

GM has issued a service bulletin for certain units of the GMC Sierra, GMC Yukon and GMC Hummer EV due to an issue with the brake control switch.

The problem: affected vehicles equipped with the Integrated Trailer Brake (RPO code JL1) may have a “Service Trailer Brake” message when connecting a trailer with an electric brake to their vehicle. Additionally, this warning may light up when the driver attempts to use the manual apply slider on switch or depress the brake pedal while towing.

The fix: certified GM technicians will be instructed to inspect the unit and replace the Trailer Brake Control Switch as necessary. It will take GM techs roughly an hour-and-a-half to perform the fix.

Affected components: Trailer Brake Control Switch.

Affected vehicles: (including all affected GM models):

Number of affected vehicles: it’s currently unclear how many vehicles are affected by the service bulletin.

Owners should: wait to be contacted by GM or schedule an appointment with their local GMC dealership to have the service bulletin performed. Notably, this Customer Service Program will only be in effect until March 31st, 2025.

Contacts:

  • GM Customer Satisfaction Program Number: N222384930
  • GMC Customer Service: 1-800-462-8782

It’s worth noting that the vast majority of vehicles affected by this service bulletin ride on the GM T1 platform, with the GMC Hummer EV being the only exception. GM’s all-electric supertruck rides on the GM BT1 platform, and utilizes Ultium battery and Ultium Drive motors for motivation as opposed to the ICE engines used by the other vehicles.

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Comments

  1. This is crazy. These are brand new vehicles! Don’t they test this stuff before they sell it?

    Reply
  2. What’s even more crazy is, my trailer brake turns on and off intermittently as I’m driving and braking while towing my Toy Hauler. In my opinion this is a huge safety concern when towing 20K lbs+.

    Reply
  3. Richard, my 5th wheel does the same thing

    Reply

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