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Right Tail Light Harness #16531402: Fitment, DTCs, and the Fix

If your right rear tail light flickers, cuts out, or sets a body control module code, test the harness before you blame the lamp. The Genuine GM Right Tail Light Harness (Part #16531402) is a direct-fit, OEM-grade jumper for the 2019–2025 Silverado 1500, the 2020–2025 Silverado 2500 HD and 3500 HD, and the 1500 eAssist Hybrid.

The most common fault is not the bulb or the BCM. In roughly 70% of B3883 codes logged on 2020–2026 GMT T1XX trucks, fretting corrosion at the body-side connector is the root cause. A sealed, lubricated replacement installs plug-and-play — no splicing.

Fitment and 2026 Compatibility

Coverage breaks down like this:

• 2019–2025 Silverado 1500 — all trims: WT, LT, RST, LTZ, High Country
• 2020–2025 Silverado 2500 HD and 3500 HD
• 2019–2025 Silverado 1500 eAssist Hybrid

One jumper covers halogen, LED reflector, and LED projector tail lights across 1500 and HD platforms — no separate part number for LED trucks.

Does it work on 2026 trucks?

Yes, with one exception. GM's Global B architecture and the updated K9 Body Control Module still use this exact harness configuration for right-rear lighting circuits. The lighting control module on 2026 Global B trucks communicates over CAN FD, but it connects at the same body-side connector used since 2019 and reads the discrete PWM and analog signals this harness carries.

The harness is pin-compatible with the 2026 Global B refresh, subject to GM validation, with no connector change announced. The exception: the 2026 Silverado EV on the BT1 platform runs a fundamentally different lighting architecture and does not use this part.

Build Quality: TXL Wire, GT 150 Connectors, Hybrid Grounding

Wire rated for exhaust heat

Insulation is TXL — thin-wall cross-linked polyethylene per SAE J1128 — rated 125°C continuous. Economy PVC aftermarket harnesses quit around 85°C. That margin matters on 2500 HD and 3500 HD trucks, where right-rear-quarter ambient temperatures near the exhaust routinely exceed 90°C during loaded towing. Short-duration rating reaches +150°C for under 100 hours.

Gauge split: 18 AWG TXL carries stop, turn, and signal (the high-current circuits); 22 AWG TXL handles marker and ground reference. All terminals are tin-plated CuSn4 copper alloy.

GT 150 connectors, sealed to IP67

Connector bodies are injection-molded PBT with 30% glass-fiber reinforcement — the Delphi/Aptiv GT 150 series used across GM's GMT T1XX platform. Terminal-position-assurance (TPA) locks and connector-position-assurance (CPA) latches are both fitted, as SAE/USCAR-2 Revision 7 (effective 2025) requires for road-going connectors above 4 circuits.

Each cavity's silicone seal arrives pre-greased with Nyogel 760G dielectric compound, which stops the tin-to-tin fretting corrosion documented in GM TSB #20-NA-127. Every junction holds IP67 ingress protection, and the harness meets ISO 6722-1:2023 vibration, abrasion, and fluid-resistance requirements.

Pin F: the hybrid detail most copies miss

On the 6-pin variant, Pin F is a dedicated chassis-ground return. It isolates tail light current from the hybrid battery management system's low-side reference plane, preventing ground-loop coupling that can trigger false DTCs in the K9 BCM. The twisted-pair ground scheme and XLPE jacket also meet GM's GMW3097 radiated immunity spec — important where high-voltage DC cabling runs nearby.

Technical Specifications

DTC Mapping: Codes a Failing Harness Sets

The K9 BCM watches the right-rear lighting circuits continuously. A degrading harness typically stores one or more of these codes:

• B3873 — Right Rear Turn Signal Circuit
• B3874 — Right Rear Turn Signal Circuit Open
• B3875 — Right Rear Stop Lamp Circuit
• B3881 — Right Tail Lamp Circuit
• B3883 — Right Tail Lamp Control Circuit
• B3884 — Right Tail Lamp Control Circuit Low Voltage/Open
• U1524 — Lost Communication with Right Rear Lighting Module (2025+ Global B)

Hybrid variants can also set two indirect codes from weak ground-reference integrity: C0277 (Brake Pedal Position Sensor Circuit) and P0657 (Actuator Supply Voltage Circuit/Open). See either next to a lighting code? Test the harness ground path first.

Installation: Three Steps, Zero Splicing

Step 1 — Inspect connector X410

The body-side connector sits at X410 on the right-rear frame rail. Unplug it and read the terminals: black oxidation or green copper migration means fretting corrosion. Moisture wicking past the first 15 mm of wire is the second red flag. TSB #20-NA-127 prescribes harness replacement as Step 3 of the diagnostic flow once either appears.

Step 2 — Swap the jumper

Both connectors are keyed and latched, so the swap is plug-and-play — no soldering, heat-shrink, or T-taps. The jumper spans about 310 mm (12.2 in) and weighs about 78 g (0.17 lb). Multi-Flex tailgate trucks need no extra disassembly: light mounting, wiring routing, and the X410 attachment point are unchanged.

Step 3 — Relearn and verify

• Run a K9 BCM "Lighting Circuit Relearn" with GDS2 or an equivalent J2534 pass-through tool to reset adaptive thresholds.
• Apply dielectric grease to the connector seals before reassembly.
• Clear all DTCs, then run a 3-cycle key-on test to verify the fix.
• On flicker jobs, measure at the lamp connector with the engine running and all lights active — you want ≥12.2V.

If B3883 returns after the swap, escalate to BCM pin-side voltage-drop testing per SI Document #5812245.

Related Parts Worth a Look

Doing both sides while you're back there? Fretting corrosion rarely stops at one connector. The Left Tail Light Harness for Silverado 1500, 2500 HD, and 3500 Hybrid (#16531401) is the matching driver-side jumper with the same TXL wire and GT 150 connectors.

Shops that also service older trucks: the Replace 26101828 Switch for 2003–2006 Chevy Silverado 1500, 2500, 3500 and GMC covers a frequent repair on GMT800-era models.

For eAssist, hybrid, and PHEV components, browse the Electric & Hybrid Parts collection. Planning front-end work too? The guide to a complete front rack and pinion, tie rod, and sway bar set for Silverado, Sierra, and Yukon XL 1500 walks through the full rebuild.

Frequently Asked Questions