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My own 2021 Silverado 2500HD, the truck behind these electrical gremlins
I love my white 2021 Silverado 2500HD 6.6 gas. It’s lifted on 37×12.50R20 Toyo Open Country R/T Trails, has a real key, and doesn’t have a pile of fluff sensors. Even a simple truck can have electrical gremlins, though, and mine has three that drive me nuts:
Wipers. The intermittent setting won’t keep consistent timing, and sometimes the wipers lift about an inch, pause, and never finish the wipe.
Bluetooth. Sometimes it plays Spotify even when the app is closed on my phone. Sometimes it does nothing, and sometimes it won’t connect at all.
A rear turn signal recently came on by itself. (Spoiler: this one wasn’t a gremlin at all.)
I went through GM’s service bulletins, NHTSA recalls, and owner forums looking for answers. Here’s what I found, with sources, plus the bigger known issues on 2020–2024 HDs.
Quick primer: “PI” (Preliminary Information) and “NA” bulletins are dealer guidance, not free repairs. Recalls are free, so check your VIN at >nhtsa.gov/recalls.
Gremlin #1: Intermittent Wipers That Stutter or Stop Mid-Wipe
I couldn’t find an HD-specific GM bulletin for this, so here’s what the evidence points to:
The multifunction switch (left stalk). On these trucks, one “multi-purpose” switch assembly handles the turn signals, hazards, and wipers. GM part 84924354 is listed for 2019–2023 Silverado/Sierra and sells for about $36–37 (>GMPartsGiant, >ChevyPartsDeal). A 2021 2500HD owner on GM-Trucks.com whose wipers wouldn’t shut off says replacing that switch fixed it. They describe it as a one-screw column-cover job (>GM-Trucks forum). The intermittent delay is set by that same stalk, so a worn switch is a logical suspect for erratic timing.
The wiper motor’s park switch. Go-Parts says wipers that stop partway across the glass usually point to the park switch inside the motor rather than the linkage (>Go-Parts).
Linkage under the cowl. Stuttering, out-of-sync arms, or clunking point to the wiper transmission’s ball sockets, according to the same Go-Parts guide. One DuramaxForum owner found mouse-nest debris that had popped a linkage ball socket off (>DuramaxForum).
The control side. A mechanic answering a 2020 2500HD owner on JustAnswer notes that the body control module (BCM) controls the wipers. He suggests checking the underhood wiper fuse and the BCM fuses, then checking for power at the motor connector. Power at the motor points to the motor, and no power points to the BCM or wiring (>JustAnswer).
Where I’m at: I haven’t fixed mine yet. My plan is to check the fuses, pop the cowl to inspect the linkage, then try the $37 switch before anything pricier. I’ll update this post when I fix it.
Gremlin #2: Bluetooth Plays Spotify on Its Own, Won’t Connect, or Does Nothing
Radio software. GM bulletin 22-NA-085 releases radio software 135120 for 2020–2022 Silverado/Sierra 2500HD/3500HD with the IOR radio. It’s a cumulative “continuous improvement” update covering software anomalies, and it includes all earlier fixes. Most trucks get it over the air, but fleet trucks, unconnected trucks, or trucks where the update was declined may need a dealer to flash it (>22-NA-085). An earlier IOR update (20-NA-012, for 2020 HDs) listed phone-projection and stability fixes (>20-NA-012). Neither bulletin specifically mentions Spotify autoplay. Check your radio’s update screen (Settings → Updates) and your RPO sticker for “IOR.”
The “plays when closed” part is often the phone. When a phone connects to a car over Bluetooth, the car can send a “play” command, and Spotify users report the app launching or playing automatically on connect (>Spotify Community, >r/Silverado). Android Auto users can turn off “start media automatically” in the phone’s Android Auto settings.
Basic reset that’s worth trying: delete the pairing on both the truck and the phone, remove old devices from the truck’s list, update the phone’s OS and Spotify, then re-pair.
If you’re fighting the same thing, start with the radio update check and a clean re-pair, because they’re free.
Gremlin #3 (Solved!): A Rear Turn Signal Came On by Itself
I was ready to blame wiring. It turned out to be a low tire, and the truck was telling me about it on purpose. I had no idea it did that.
Tire Fill Alert. The 2021 HD owner’s manual says that on trucks equipped with Tire Fill Alert, adding air to a low tire while the truck is in Park makes that corner’s turn signal flash. When the tire reaches the recommended pressure, the horn chirps once and the lamp goes solid for a moment (>2021 Silverado HD owner’s manual, p. 345). Other owners report the same “random” flashing that turned out to be a low tire on that corner (>GM-Trucks forum). My blinker was the TPMS doing its job. The fix for a low tire is air, not a wiring harness. I wrote up how Tire Fill Alert works and how to use it.
If yours does this, check tire pressure before you touch the wiring. If all four tires are good and the signal still comes on by itself, these are the next things to look at:
The multifunction switch. One stalk switch runs the wipers and the turn signals (see Gremlin #1), so a failing switch is a logical suspect. That’s my inference, not a GM statement.
Not my year, but worth knowing: GM program N212355910 covered 2022 HDs whose turn signals stayed on after passive door locking. The fix was BCM reprogramming, and the program ran until March 31, 2024 (>N212355910).
Lifted-truck wiring: check the tail lamp and hitch connectors for chafing or corrosion.
Dead battery / parasitic draw (2022–2023 HD): In PIT5750B/C, GM says the BCM can stay awake because of shorted heated-seat LIN bus circuits 6133/4115. The places to look are a pinched harness under the left rear seat and corrosion at connector X225 (>PIT5750C). My 2021 isn’t on that bulletin, but my previous owner swapped in High Country leather seats, so if my battery ever starts dying, the seat harness connections under and behind the seats are the first place I’ll look.
2024 HD battery drain after an over-the-air update: Program N242435631 reprograms the serial data gateway module and runs until October 31, 2026 (>N242435631).
“No Content Available” radio screen (2020–2022, 8-inch display): In PIT5897A, GM tells dealers to replace the display (>PIT5897A).
“Service Trailer Brake” / DTC C1114 (2020–2024 with the integrated controller): GM’s 21-NA-155 points to poor 7-way connections. It recommends Pollak HD plugs and, for worn sockets, GM part 84056018 (>21-NA-155).
Recalls: These include the power tailgate switch shorting from water intrusion (24V-060, 24V-894) and brake modulator water intrusion with a fire risk on certain 2021–2022 trucks (21V-758) (>NHTSA).
NHTSA lists 17 “Electrical System” complaints for 2020 and for 2021 Silverado 2500s, and 29 for 2022 (>NHTSA). Those are small, self-reported numbers, not failure rates.
The Diagnostic Kit I’d Keep in an HD
A basic code reader won’t see the BCM or radio, so get a scanner that reads all GM modules.
My truck also had its fuel pump module fail, and I wrote that whole thing up separately.
FAQ
Why do my 2500HD’s intermittent wipers act erratic?
The usual suspects are the multifunction stalk switch (GM 84924354, which also runs the turn signals), the motor’s park switch, linkage sockets under the cowl, or BCM-side power. I found no HD-specific GM bulletin.
Why does my Silverado play Spotify automatically?
Often the phone responds to the truck’s “play” command on Bluetooth connect. Also make sure your IOR radio has GM’s latest software (22-NA-085 covers 2020–2022 HDs).
Why did my rear turn signal flash by itself?
On my truck, it was a low tire. Tire Fill Alert flashes that corner’s signal. If the pressures are fine, suspect the stalk switch or the rear-lamp wiring.
Are there electrical recalls on the 2020–2024 2500HD?
Yes: tailgate switch (24V-060, 24V-894) and brake modulator (21V-758) on certain trucks. Check your VIN.
Bulletin, recall, and complaint data was retrieved October 18, 2026.
A rear turn signal blinking on its own on a 2020+ Silverado/Sierra HD is often Tire Fill Alert flagging a low tire. How the feature works, how to use it, and TPMS tips from the owner’s manual.
My 2021 Silverado 2500HD 6.6 gas lost its fuel pump module at 65k miles. Symptoms, the GM bulletins, why my VIN didn’t qualify for a recall, parts, and real cost ranges.
