B2575 on 2014-2016 GMC Sierra 1500: Headlight Circuit Fault Causes and Fixes

What's Unique About the 2014-2016 Gmc SIERRA 1500

For the 2014-2016 GMC Sierra and its platform mate, the Chevy Silverado, code B2575 is most famously associated with a specific, well-documented issue involving aftermarket snowplow lighting systems. Multiple Technical Service Bulletins (TSBs) point to this code being set when switching between the truck's factory headlights and the plow's headlights. Unlike older vehicles, this Sierra generation does not use traditional, user-replaceable relays for the headlights; the function is integrated into the Body Control Module (BCM). The BCM can shut down the circuit for protection if it detects a fault, requiring a specific reset procedure after the repair to restore power.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Left low-beam headlight is inoperative
• Left low-beam headlight flickers or works intermittently
• Headlight inoperative message on the driver information center (DIC)
• In some cases with aftermarket wiring, the headlight may stay on and cannot be turned off.

Most Likely Causes

1. Improperly Installed Aftermarket Snowplow Lighting 🔴 High Probability This is a widely documented issue confirmed by multiple GM Technical Service Bulletins (TSBs like PIT5412D). The factory BCM is sensitive to the electrical load and switching methods of aftermarket plow systems.
   How to confirm: Check if the code appeared after installing or using a snowplow. Review the wiring installation and compare it to the guidelines in GM Upfitter Integration Bulletin 116, which is the official procedure.
   Typical fix: Correct the snowplow wiring harness installation according to the plow manufacturer's and GM's specifications. This often involves installing a specific isolation module or harness adapter designed for the K2XX platform to prevent feedback to the BCM.
   Est. part cost: $50-$200
2. Faulty or Incompatible Aftermarket Headlight Bulb (LED/HID) 🟡 Medium Probability The BCM monitors circuit resistance and current. Low-power LED bulbs without a built-in CANbus-compatible resistor can trick the BCM into thinking the bulb is burned out or the circuit is open, triggering the code.
   How to confirm: Swap the aftermarket bulb with a standard OEM-spec halogen bulb. If the code disappears (after a BCM reset) and the light works, the aftermarket bulb is the cause.
   Typical fix: Replace the bulb with a high-quality, CANbus-compatible LED bulb, or install an inline load resistor (typically a 6-ohm, 50-watt resistor) on the headlight power and ground wires. Reverting to OEM-spec halogen bulbs is the most reliable solution.
   Est. part cost: $20-$100
3. Damaged Wiring or Connector 🟡 Medium Probability
   How to confirm: Visually inspect the wiring harness leading to the left headlight assembly for any signs of fraying, melting, corrosion, or loose pins in the connector. A burnt or discolored connector is a common finding. Perform a continuity and short-to-ground test on the control circuit wire between the BCM and the headlight. The ground for the left headlamp is G106, located on the front center of the frame cross rail.
   Typical fix: Repair the damaged section of wire or replace the headlight pigtail connector. 🎬 Watch: How to remove the headlight assembly for easier access. Aftermarket pigtails like Dorman 645-940 or part number 33482-0801 are available.
   Est. part cost: $15-$50
4. Burnt-Out Headlight Bulb ⚪ Low Probability
   How to confirm: Visually inspect the bulb's filament. Swap the left and right low-beam bulbs to see if the problem moves to the other side. Remember to reset the BCM after swapping.
   Typical fix: Replace the burnt-out headlight bulb. For 2014-2015 models, this is a single 9012 (HIR2) bulb that serves as both the low and high beam via a mechanical shutter inside the headlight assembly. For 2016 models, it may be a D5S (HID), H11 (low beam reflector), or 9012 bulb depending on trim.
   Est. part cost: $20-$40

Rare But Worth Checking

• Faulty Body Control Module (BCM): This is rare and should only be considered after all other possibilities have been exhausted. A misdiagnosis is common because the BCM will disable the circuit after a fault is detected and won't re-enable it until it's properly reset. If replacement is necessary, a new BCM (such as GM part #13594764 or #13506935) must be programmed by a dealer or a qualified shop.
• Faulty Headlight Switch: While uncommon, the multifunction switch on the steering column can fail, sending an incorrect signal to the BCM. This is usually accompanied by other lighting issues (e.g., turn signals, high beams) and is less likely to set a single-side code like B2575.

Diagnosis Steps

1. Scan the BCM for codes. Confirm if B2575 is present, and check for its counterpart, B2699 (Right Headlamp).
2. If a snowplow or other major front-end electrical accessory is installed, investigate its wiring first. This is the most likely cause. Consult GM Upfitter Bulletin 116.
3. If no plow is present, inspect the left low-beam headlight bulb. Check if it's burnt out or an incompatible aftermarket LED/HID bulb. Swap with the known-good bulb from the right side to verify.
4. Inspect the headlight connector pigtail for signs of melting, corrosion, or burnt terminals. These connectors are a known failure point.
5. Check fuse #59 (for 2014-2017 models) in the under-hood fuse block. This fuse often protects the BCM circuits that power the headlights.
6. If a repair is made (e.g., bulb replaced, wire fixed), you MUST perform a hard reset of the BCM. Turn the ignition off, disconnect the negative battery terminal, then disconnect the positive terminal. Touch the two disconnected cable ends together for 30-60 seconds to drain the capacitors in the modules.
7. Reconnect the positive battery terminal, then the negative. Clear any remaining DTCs with a scan tool and re-test the headlight function.
8. If the problem persists, use a professional scan tool with bidirectional controls (like GM's GDS2) to command the left headlight on. If it turns on, the issue is with an input to the BCM (e.g., headlight switch). If it does not turn on, the fault is in the BCM's output driver, the wiring, or the bulb.
9. If wiring is suspected, check the integrity of the ground connection at G106, located on the front center of the frame cross rail under the crank pulley.

Parts You'll Likely Need

• Headlight Bulb (Low/High Beam) (OEM #ACDelco 9012 (HIR2)) — A burnt-out or incompatible bulb is a common cause. 2014-2015 models often use a single 9012 (HIR2) bulb for both low and high beams. 2016 models vary by trim.
  Trusted brands: ACDelco, Sylvania, Philips
  OEM price range: $30-$50
  Aftermarket price range: $20-$40
• Headlight Wiring Harness Connector (Pigtail) — The connector at the back of the headlight assembly can melt or corrode from resistance, causing an open or short circuit. This is a very common point of failure.
  Trusted brands: ACDelco PT2703, Dorman 645-940, Standard Motor Products S-553
  OEM price range: $30-$60
  Aftermarket price range: $15-$30
• Body Control Module (BCM) (OEM #13594764, 13506935) — A rare but possible cause of the fault. Replacement requires professional programming to the vehicle's VIN.
  Trusted brands: ACDelco (OEM)
  OEM price range: $250-$400
  Aftermarket price range: $150-$300 (Remanufactured)

Related Codes That Often Appear With This One

• B2699 — B2699 is the equivalent code for the Right Headlamp Control Circuit. They often appear together, especially when the fault is caused by an aftermarket accessory like a snowplow that is wired to tap into both headlight circuits.

Technical Service Bulletins (TSBs) & Recalls

• PIT5412D / PIT5412C / PIT5412A: Documents the link between code B2575/B2699 and issues with snowplow headlight operation, advising technicians to consult upfitter bulletins.
• PI1222A: Explains that the BCM will enter a protective 'latched' state after detecting a short, and that it must be reset by disconnecting the battery to restore function after a repair.
• GM Upfitter Integration Bulletin 116: The official GM document detailing the correct procedures for wiring aftermarket accessories like snowplows to avoid setting codes like B2575.

Platform-Specific Known Issues

• A GM Technical Service Bulletin (PI1222A) notes that after a circuit fault is repaired, the BCM may not power the circuit again until it is reset by disconnecting the battery for at least 30 seconds.
• TSB PIT5412D specifically calls out this code in relation to flickering or inoperative headlights after a snowplow installation, directing technicians to consult GM Upfitter Bulletin 116 for correct wiring procedures.
• The use of a single 9012 bulb for both high and low beams in 2014-2015 models means a failure of the bulb filament will knock out both functions, though the mechanical shutter mechanism is rarely the cause of a B2575 code.

Mechanic-Grade Diagnostic Values

• Headlight Circuit Fuse — expected: Fuse #59 (2014-2017) or #58 (2018) in the under-hood fuse block should have continuity.. Failure: An open or blown fuse indicates a short circuit that must be found before replacing the fuse.

Scan Tool Commands That Help

• GDS2 (GM Global Diagnostic System 2) or equivalent professional scan tool: BCM Output Control - Left Low Beam Headlamp Command — Use this after a hard reset fails to restore light function. It directly commands the BCM's internal driver to power the circuit, bypassing the regular switches. If the light works with this command, the BCM, wiring, and bulb are good, and the fault is on the input side (e.g., headlight switch). If it does not work, the fault is the BCM driver, wiring, or bulb.

Wiring & Ground Locations

• G106 — On the front center of the frame cross rail, located under the crank pulley.. This is the primary ground point for the left front lighting, including the low beam headlamp. A loose or corroded connection here will cause high resistance or an open circuit, triggering B2575.
• G103 — At the left rear of the engine compartment on the cowl, above the brake booster.. This is a main ground for the Body Control Module (BCM). While a fault here would likely cause multiple other issues, an intermittent connection could contribute to erratic BCM behavior, including false fault codes.
• K9 BCM Connector X5 — One of the large multi-pin connectors on the Body Control Module, typically located under the driver's side of the dashboard.. The power control wire for the left low beam originates from a pin on this connector. Checking for voltage here during a bidirectional test can isolate the fault to the BCM itself.

Real Owner Repair Stories

• Multiple YouTube videos and forum threads (2014-2016 Chevrolet Silverado / GMC Sierra) — Left (or right) headlight suddenly stopped working. Code B2575 is present. Replacing the bulb did not fix the issue.
  ❌ Tried (didn't work) Replacing the headlight bulb, Checking fuses, Performing a BCM reset by disconnecting the battery
  ✅ What actually fixed it The headlight pigtail connector at the back of the headlight assembly had melted. The plastic housing was discolored and brittle, and the metal terminals inside were burnt, causing a poor connection. The fix was to cut off the old connector and splice in a new replacement pigtail harness.

OEM Part Supersession History

• 13506935, 13587704, 13592137 → 13594764 — Standard part consolidation and revision by the manufacturer.
  Heads up: These BCMs are vehicle-specific and store VIN and security information. A replacement module, even with the correct part number, must be cloned from the original or programmed by a dealer to function. A used module from another vehicle will not work without programming.

Model Year Variations Within This Range

• 2014-2015: Most trims use a single 9012 (HIR2) dual-filament bulb for both low and high beams in a projector housing.
• 2016: This was a refresh year with multiple headlight options. Higher trims (like Denali) with factory HID headlights use a D5S bulb. Lower trims with reflector housings use a separate H11 bulb for the low beam and a 9005 for the high beam. It is critical to identify the correct headlight system before purchasing parts.