GM bulletin 21-NA-135
What it saysThis service bulletin provides information to inform dealership personnel about Law Enforcement and Government vehicles that request to disable or enable content. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 28, 2025, received Jan 25, 2023, about the electrical system — 3 documents under this number. It names 265 model years across Chevrolet, GMC, Buick and Cadillac (2019–2025). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC · Buick · Cadillac.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin provides information to inform dealership personnel about Law Enforcement and Government vehicles that request to disable or enable content.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 21-NA-135 | Service bulletin | Jan 28, 2025 | 11014222 | PDF, 125 KB |
| 21-NA-135 | Service bulletin | Nov 16, 2023 | 10245559 | PDF, 70 KB |
| 21-NA-135 | Service bulletin | Jan 13, 2023 | 10230612 | PDF, 47 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themChevrolet 124 model years
and 77 more on this site: 2020 Chevrolet Equinox, 2019 Chevrolet Equinox, 2024 Chevrolet Express, 2023 Chevrolet Express, 2022 Chevrolet Express, 2021 Chevrolet Express, 2020 Chevrolet Express, 2019 Chevrolet Express, 2020 Chevrolet Impala, 2019 Chevrolet Impala, 2025 Chevrolet Malibu, 2024 Chevrolet Malibu, 2023 Chevrolet Malibu, 2022 Chevrolet Malibu, 2021 Chevrolet Malibu, 2020 Chevrolet Malibu, 2019 Chevrolet Malibu, 2025 Chevrolet Silverado, 2024 Chevrolet Silverado, 2023 Chevrolet Silverado, 2022 Chevrolet Silverado, 2021 Chevrolet Silverado, 2020 Chevrolet Silverado, 2019 Chevrolet Silverado, 2025 Chevrolet Silverado 2500HD, 2024 Chevrolet Silverado 2500HD, 2023 Chevrolet Silverado 2500HD, 2022 Chevrolet Silverado 2500HD, 2021 Chevrolet Silverado 2500HD, 2020 Chevrolet Silverado 2500HD, 2019 Chevrolet Silverado 2500HD, 2025 Chevrolet Silverado 3500HD, 2024 Chevrolet Silverado 3500HD, 2023 Chevrolet Silverado 3500HD, 2022 Chevrolet Silverado 3500HD, 2021 Chevrolet Silverado 3500HD, 2020 Chevrolet Silverado 3500HD, 2019 Chevrolet Silverado 3500HD, 2020 Chevrolet Sonic, 2019 Chevrolet Sonic, 2022 Chevrolet Spark, 2021 Chevrolet Spark, 2020 Chevrolet Spark, 2019 Chevrolet Spark, 2025 Chevrolet Suburban, 2024 Chevrolet Suburban, 2023 Chevrolet Suburban, 2022 Chevrolet Suburban, 2021 Chevrolet Suburban, 2020 Chevrolet Suburban, 2019 Chevrolet Suburban, 2025 Chevrolet Tahoe, 2024 Chevrolet Tahoe, 2023 Chevrolet Tahoe, 2022 Chevrolet Tahoe, 2021 Chevrolet Tahoe, 2020 Chevrolet Tahoe, 2019 Chevrolet Tahoe, 2025 Chevrolet Trailblazer, 2024 Chevrolet Trailblazer, 2023 Chevrolet Trailblazer, 2022 Chevrolet Trailblazer, 2021 Chevrolet Trailblazer, 2025 Chevrolet Traverse, 2024 Chevrolet Traverse, 2023 Chevrolet Traverse, 2022 Chevrolet Traverse, 2021 Chevrolet Traverse, 2020 Chevrolet Traverse, 2019 Chevrolet Traverse, 2025 Chevrolet Trax, 2024 Chevrolet Trax, 2022 Chevrolet Trax, 2021 Chevrolet Trax, 2020 Chevrolet Trax, 2019 Chevrolet Trax, 2019 Chevrolet Volt.
Also filed against model years this site has no page for: 2019 Chevrolet 6500; 2024 Chevrolet Bolt EV; 2019 Chevrolet Duplicate Silverado 5500; 2021 Chevrolet Onix; 2019 Chevrolet Trailblazer; 2020 Chevrolet Trailblazer; 2023 Chevrolet Trax.
GMC 60 model years
and 50 more on this site: 2024 GMC Canyon, 2023 GMC Canyon, 2022 GMC Canyon, 2021 GMC Canyon, 2020 GMC Canyon, 2019 GMC Canyon, 2025 GMC Hummer EV, 2024 GMC Hummer EV, 2023 GMC Hummer EV, 2025 GMC Savana, 2024 GMC Savana, 2023 GMC Savana, 2022 GMC Savana, 2021 GMC Savana, 2020 GMC Savana, 2019 GMC Savana, 2025 GMC Sierra, 2024 GMC Sierra, 2022 GMC Sierra, 2021 GMC Sierra, 2020 GMC Sierra, 2019 GMC Sierra, 2025 GMC Sierra 2500HD, 2024 GMC Sierra 2500HD, 2023 GMC Sierra 2500HD, 2022 GMC Sierra 2500HD, 2021 GMC Sierra 2500HD, 2020 GMC Sierra 2500HD, 2019 GMC Sierra 2500HD, 2025 GMC Sierra 3500HD, 2024 GMC Sierra 3500HD, 2023 GMC Sierra 3500HD, 2022 GMC Sierra 3500HD, 2021 GMC Sierra 3500HD, 2020 GMC Sierra 3500HD, 2019 GMC Sierra 3500HD, 2025 GMC Terrain, 2024 GMC Terrain, 2023 GMC Terrain, 2022 GMC Terrain, 2021 GMC Terrain, 2020 GMC Terrain, 2019 GMC Terrain, 2025 GMC Yukon, 2024 GMC Yukon, 2023 GMC Yukon, 2022 GMC Yukon, 2021 GMC Yukon, 2020 GMC Yukon, 2019 GMC Yukon.
Also filed against model years this site has no page for: 2024 GMC 3500HD; 2022 GMC Hummer EV Pickup.
Buick 28 model years
and 19 more on this site: 2025 Buick Encore, 2024 Buick Encore, 2023 Buick Encore, 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore, 2019 Buick Encore, 2025 Buick Envision, 2024 Buick Envision, 2023 Buick Envision, 2022 Buick Envision, 2021 Buick Envision, 2020 Buick Envision, 2019 Buick Envision, 2025 Buick Envista, 2024 Buick Envista, 2019 Buick LaCrosse, 2020 Buick Regal, 2019 Buick Regal.
Also filed against model years this site has no page for: 2020 Buick Lacrosse.
Cadillac 53 model years
and 40 more on this site: 2024 Cadillac CT5, 2023 Cadillac CT5, 2022 Cadillac CT5, 2021 Cadillac CT5, 2020 Cadillac CT5, 2020 Cadillac CT6, 2019 Cadillac CT6, 2019 Cadillac CTS, 2025 Cadillac Escalade, 2024 Cadillac Escalade, 2023 Cadillac Escalade, 2022 Cadillac Escalade, 2021 Cadillac Escalade, 2020 Cadillac Escalade, 2019 Cadillac Escalade, 2025 Cadillac Lyriq, 2024 Cadillac Lyriq, 2023 Cadillac Lyriq, 2025 Cadillac Optiq, 2025 Cadillac XT4, 2024 Cadillac XT4, 2023 Cadillac XT4, 2022 Cadillac XT4, 2021 Cadillac XT4, 2020 Cadillac XT4, 2019 Cadillac XT4, 2025 Cadillac XT5, 2024 Cadillac XT5, 2023 Cadillac XT5, 2022 Cadillac XT5, 2021 Cadillac XT5, 2020 Cadillac XT5, 2019 Cadillac XT5, 2025 Cadillac XT6, 2024 Cadillac XT6, 2023 Cadillac XT6, 2022 Cadillac XT6, 2021 Cadillac XT6, 2020 Cadillac XT6, 2019 Cadillac XTS.
Also filed against model years this site has no page for: 2021 Cadillac CT6; 2023 Cadillac Redundant Lyriq; 2024 Cadillac Redundant Lyriq; 2019 Cadillac SRX; 2020 Cadillac XTS.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 250 model years this bulletin names have filed 23,187 complaints with NHTSA since 2015. 12,949 of them name Engine, Electrical System, Exterior Lighting — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2019 Chevrolet Silverado, the 142 owners who gave an odometer reading for Engine reported it at a median of 71,396 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
In the early morning hours of october 21st, around 3am, we were woken up by smoke/fire alarms. We started running around our home to identify the cause of the alarm. After about 5 minutes of searching inside the home and finding nothing, we realized that there was some smell of smoke coming from the garage and when the mudroom door which…
2019 Chevrolet Bolt EV · Electrical System · filed with NHTSA Oct 30, 2020
My Traverse prompted me to do an update - I did- and all my cameras stopped working- took to dealership - they tried to do a Manuel update and locked up the whole system- and the USB’s stopped working - 4 weeks later waiting on new system and no answer in site for when parts will be in - contacted GM and they escalated issue - told to be…
2025 Chevrolet Traverse · Electrical System · filed with NHTSA Jul 22, 2025
Driving home tonight there was a car in front of me so my low beams were on. I saw a deer approaching from the right side of the roadway while at the same time dropping down into a small dip in the road and because the headlights are so low I lost sight of the deer as it was then in the shadows with no illumination because the headlights…
2022 Chevrolet Traverse · Exterior Lighting · filed with NHTSA Dec 28, 2022
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the electrical system
Source: same model, same component group625 other manufacturer communications filed against these GM models under the same component group (electrical system), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N242468490-02 | Service campaign | May 28, 2026 | Certain vehicles may have missing cavity plugs from the rear chassis harness electrical connector. Dealers are to inspect the rear chassis h… |
| N252529080 | Service campaign | Apr 1, 2026 | Service Update. Certain vehicles listed above may be missing a high voltage header plug on the RESS battery pack drive motor connector. Dea… |
| N252515590 | Service campaign | Jan 27, 2026 | Certain vehicles listed above, may have a condition in which the body-to-chassis ground strap may be corroded. Dealers will replace the grou… |
| 24-NA-166 | Service bulletin | Nov 7, 2025 | This technical bulletin provides repair information to correct a customer concern of DTC C1171 C1172 C1173 C1174 Tire Pressure Monitor Senso… |
| 24-NA-227 | Service bulletin | Nov 4, 2025 | This technical bulletin provides repair information to correct a customer concern of Vibration Rattle or Boom at 1800 to 2000 RPM. |
| 25-NA-061 | Service bulletin | Oct 3, 2025 | This technical bulletin provides a procedure to correct the condition of Driver or Passenger Rear Door Handle Will Not Fold In. |
| 25-NA-074 | Service bulletin | Sep 4, 2025 | Some customers may comment on rear body structure stop lamp or rear closure signal lamp may be totally inoperative or staying illuminated. |
| 18-NA-180 | Service bulletin | Sep 4, 2025 | This Warranty Administration service bulletin provides Lithium-Ion battery Exchange Process and Transaction Submission information. |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet, GMC, Buick and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 21-NA-135 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the 21-NA-135 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way.
Which vehicles does 21-NA-135 cover?
The manufacturer filed it against 265 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2019 Buick Cascada, 2025 Buick Enclave, 2024 Buick Enclave, 2023 Buick Enclave, 2022 Buick Enclave, 2021 Buick Enclave and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.