74 Electrical connector parts are listed for the 2021 GMC Sierra 2500, in 37 part types, covering both the 6.6L V8 and the 6.6L V8 DIESEL Turbocharged. Each one has a brand, a manufacturer part number and notes that say where it fits.
On the 2021 GMC Sierra 2500, the connector system supplies the pigtails and connector bodies that terminate the vehicle harness at lamps, sensors and modules. Most of the listed parts are Trailer Connector (14 parts), Chassis Wiring Harness / Connector (4 parts) and Park Assist (PAS) Camera Connector (4 parts). The other 34 part types cover the remaining 52 parts.
The 2021 GMC Sierra 2500 was sold with both the 6.6L V8 and the 6.6L V8 DIESEL Turbocharged. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2021 GMC Sierra 2500 electrical connector parts are STANDARD MOTOR PRODUCTS (26 parts), GM GENUINE (17 parts) and CURT (17 parts), plus 8 more brands.
3 parts on this 2021 GMC Sierra 2500 page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including CURT 55415 (Trailer Connector) and CURT 56229 (Trailer Connector). Click any part number to see every vehicle that part fits.
Accelerator Pedal Position Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S1478 | 🇺🇸 US 🇨🇦 CA | Connector Shape: Rectangle | View on Amazon |
This table covers the harness connectors at the Accelerator Pedal Position Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S1478.
Alternator / Generator Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S1477 | 🇺🇸 US 🇨🇦 CA | without Wiring Harness | View on Amazon |
This table covers the harness connectors at the Alternator / Generator. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S1477.
Brake Pad Wear Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2936 | 🇺🇸 US 🇨🇦 CA | Front | View on Amazon |
This table covers the harness connectors at the Brake Pad Wear Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
This group shows a single part: STANDARD MOTOR PRODUCTS S2936.
Brake Pedal Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2506 | 🇺🇸 US 🇨🇦 CA | Terminal Type: Blade | View on Amazon |
This table covers the harness connectors at the Brake Pedal. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
This group shows a single part: STANDARD MOTOR PRODUCTS S2506.
Camshaft Position Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HOLSTEIN Fits: 6.6L V8 DIESEL Turbocharged | 2HAR0060 | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2316 | 🇺🇸 US 🇨🇦 CA | Connector Shape: OvalNumber of Splice Connectors Included: 3 | View on Amazon |
| UNITED MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | CON62 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the harness connectors at the Camshaft Position Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
3 Camshaft Position Sensor Connector parts are listed for the 2021 GMC Sierra 2500, from HOLSTEIN, STANDARD MOTOR PRODUCTS and UNITED MOTOR PRODUCTS.
Listed part numbers: HOLSTEIN 2HAR0060, STANDARD MOTOR PRODUCTS S2316 and UNITED MOTOR PRODUCTS CON62.
Chassis Wiring Harness / Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85526683 | 🇺🇸 US 🇨🇦 CA | FrontLeft | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85533165 | 🇺🇸 US 🇨🇦 CA | Black | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 84769203 | 🇺🇸 US 🇨🇦 CA | Gender: FemaleBlack | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | PT3922 | 🇺🇸 US 🇨🇦 CA | Si Elec Code: X436Rear Axle Harness to Chassis Harness | View on Amazon |
This table covers the wiring-harness connectors at the Chassis. Typical signs include an intermittent fault that moves when you wiggle the harness, or a melted or corroded plug. Match terminal count and keyway. Repair with heat-shrink terminals, not twist-and-tape.
4 Chassis Wiring Harness / Connector parts for the 2021 GMC Sierra 2500 come from GM GENUINE.
Part numbers include GM GENUINE 85526683, GM GENUINE 85533165 and GM GENUINE 84769203, among others listed above.
Crankshaft Position Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HOLSTEIN Fits: 6.6L V8 DIESEL Turbocharged | 2HAR0060 | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2316 | 🇺🇸 US 🇨🇦 CA | Connector Shape: OvalNumber of Splice Connectors Included: 3 | View on Amazon |
This table covers the harness connectors at the Crankshaft Position Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
2 Crankshaft Position Sensor Connector parts are listed for the 2021 GMC Sierra 2500, from HOLSTEIN and STANDARD MOTOR PRODUCTS.
This group includes HOLSTEIN 2HAR0060 and STANDARD MOTOR PRODUCTS S2316.
Diesel Exhaust Fluid (DEF) Pump Wiring Harness / Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ACDELCO Fits: 6.6L V8 DIESEL Turbocharged | 84876221 | 🇺🇸 US 🇨🇦 CA | GM Original Equipment | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 87821866 | 🇺🇸 US 🇨🇦 CA | Fits 98.2" Bed141.5" Wheelbase or 162.5" Wheelbase or 172.0" Wheelbase | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85138745 | 🇺🇸 US 🇨🇦 CA | Fits 98.2" Bed141.5" Wheelbase or 162.5" Wheelbase or 172.0" Wheelbase | View on Amazon |
This table covers the wiring-harness connectors at the Diesel Exhaust Fluid (DEF) Pump. Typical signs include an intermittent fault that moves when you wiggle the harness, or a melted or corroded plug. Match terminal count and keyway. Repair with heat-shrink terminals, not twist-and-tape.
3 Diesel Exhaust Fluid (DEF) Pump Wiring Harness / Connector parts for the 2021 GMC Sierra 2500 come from 2 brands — GM GENUINE and ACDELCO.
Listed part numbers: ACDELCO 84876221, GM GENUINE 87821866 and GM GENUINE 85138745.
Differential Pressure Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DORMAN Fits: 6.6L V8 DIESEL Turbocharged | 645325 | 🇺🇸 US 🇨🇦 CA | Black | View on Amazon |
This table covers the harness connectors at the Differential Pressure Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — DORMAN 645325.
EGR Valve Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2488 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the harness connectors at the EGR Valve. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S2488.
Engine Block Heater Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 84564686 | 🇺🇸 US 🇨🇦 CA | End 1 Terminal Gender: FemaleEnd 1 Terminal Type: Pin | View on Amazon |
This table covers the harness connectors at the Engine Block Heater. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — GM GENUINE 84564686.
Exhaust Gas Temperature (EGT) Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ACDELCO Fits: 6.6L V8 DIESEL Turbocharged | 84727362 | 🇺🇸 US 🇨🇦 CA | GM Original Equipment | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2492 | 🇺🇸 US 🇨🇦 CA | Fits Rearor with Right Connector | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S3154 | 🇺🇸 US 🇨🇦 CA | Center | View on Amazon |
This table covers the harness connectors at the Exhaust Gas Temperature (EGT) Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
3 Exhaust Gas Temperature (EGT) Sensor Connector parts are listed for the 2021 GMC Sierra 2500, from STANDARD MOTOR PRODUCTS and ACDELCO.
This group includes ACDELCO 84727362, STANDARD MOTOR PRODUCTS S2492 and STANDARD MOTOR PRODUCTS S3154.
Fuel Injection Pressure Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S1713 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the harness connectors at the Fuel Injection Pressure Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S1713.
Fuel Rail Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2426 | 🇺🇸 US 🇨🇦 CA | Left | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2894 | 🇺🇸 US 🇨🇦 CA | Right | View on Amazon |
This table covers the harness connectors at the Fuel Rail. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
STANDARD MOTOR PRODUCTS supplies both parts for the 2021 GMC Sierra 2500.
Listed part numbers: STANDARD MOTOR PRODUCTS S2426 and STANDARD MOTOR PRODUCTS S2894.
Fuel Tank Pressure Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S1445 | 🇺🇸 US 🇨🇦 CA | Wiring Harness Length (In): 17Wiring Harness Length (mm): 431.8 | View on Amazon |
This table covers the harness connectors at the Fuel Tank Pressure Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
This group shows a single part: STANDARD MOTOR PRODUCTS S1445.
Headliner Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85725004 | 🇺🇸 US 🇨🇦 CA | FrontRight | View on Amazon |
This table covers the harness connectors at the Headliner. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — GM GENUINE 85725004.
HVAC Control Switch / Panel Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GPD Fits: 6.6L V8 DIESEL Turbocharged | 1713412 | 🇺🇸 US 🇨🇦 CA | with 3 Terminal(s) | View on Amazon |
This table covers the harness connectors at the HVAC Control Switch / Panel. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — GPD 1713412.
Ignition Coil Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| ACDELCO Fits: 6.6L V8 DIESEL Turbocharged | PT2368 | 🇺🇸 US 🇨🇦 CA | GoldShape: Rectangle | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | HP4485 | 🇺🇸 US 🇨🇦 CA | HandypackWiring Harness Length (mm): 304.8 | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S761 | 🇺🇸 US 🇨🇦 CA | Wiring Harness Length (mm): 304.8 | View on Amazon |
This table covers the harness connectors at the Ignition Coil. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
3 Ignition Coil Connector parts are listed for the 2021 GMC Sierra 2500, from STANDARD MOTOR PRODUCTS and ACDELCO.
Listed part numbers: ACDELCO PT2368, STANDARD MOTOR PRODUCTS HP4485 and STANDARD MOTOR PRODUCTS S761.
Knock / Detonation Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S934 | 🇺🇸 US 🇨🇦 CA | Contact Terminal Material: Metal | View on Amazon |
This table covers the harness connectors at the Knock / Detonation Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S934.
Manifold Pressure (MAP) Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| BWD/NIEHOFF Fits: 6.6L V8 DIESEL Turbocharged | PT944 | 🇺🇸 US 🇨🇦 CA | Evaporator Emission Control ConnectorAt Fuel Tank Pressure Sensor | View on Amazon |
This table covers the harness connectors at the Manifold Pressure (MAP) Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — BWD/NIEHOFF PT944.
NOx (Nitrogen Oxide) Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2912 | 🇺🇸 US 🇨🇦 CA | Upstream | View on Amazon |
This table covers the harness connectors at the NOx (Nitrogen Oxide) Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
This group shows a single part: STANDARD MOTOR PRODUCTS S2912.
Oil Pressure Sender / Switch Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2882 | 🇺🇸 US 🇨🇦 CA | Connector Shape: RectangularHarness Length | View on Amazon |
This table covers the harness connectors at the Oil Pressure Sender / Switch. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
This group shows a single part: STANDARD MOTOR PRODUCTS S2882.
Park Assist (PAS) Camera Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 84852715 | 🇺🇸 US 🇨🇦 CA | Fits RearSLT Model | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 84478448 | 🇺🇸 US 🇨🇦 CA | FrontAT4 Model or Denali or SLT Model | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85063186 | 🇺🇸 US 🇨🇦 CA | RearCrew Cab Pickup | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85132580 | 🇺🇸 US 🇨🇦 CA | Fits RearBase Model | View on Amazon |
This table covers the harness connectors at the Park Assist (PAS) Camera. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
4 Park Assist (PAS) Camera Connector parts for the 2021 GMC Sierra 2500 come from GM GENUINE.
Listed part numbers: GM GENUINE 84852715, GM GENUINE 84478448 and GM GENUINE 85063186, plus the other parts above.
Parking Aid Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HOLSTEIN Fits: 6.6L V8 DIESEL Turbocharged | 2HAR0060 | 🇺🇸 US 🇨🇦 CA | Front And Rear | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2316 | 🇺🇸 US 🇨🇦 CA | Connector Shape: OvalNumber of Splice Connectors Included: 3 | View on Amazon |
This table covers the harness connectors at the Parking Aid Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
2 Parking Aid Sensor Connector parts are listed for the 2021 GMC Sierra 2500, from HOLSTEIN and STANDARD MOTOR PRODUCTS.
Part numbers include HOLSTEIN 2HAR0060 and STANDARD MOTOR PRODUCTS S2316.
Parking Brake Actuator Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S1414 | 🇺🇸 US 🇨🇦 CA | Connector Shape: RectangleTerminal Type: Blade | View on Amazon |
This table covers the harness connectors at the Parking Brake Actuator. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S1414.
Power Steering Assist Motor / Module Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 23365214 | 🇺🇸 US 🇨🇦 CA | Crew Cab PickupMag Speed Variable Assist Power Steering(NV8) | View on Amazon |
This table covers the harness connectors at the Power Steering Assist Motor / Module. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
This group shows a single part: GM GENUINE 23365214.
Radio Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| METRA Fits: 6.6L V8 DIESEL Turbocharged | AXBUCHGM2 | 🇺🇸 US 🇨🇦 CA | Rear View Camera Harness | View on Amazon |
| METRA Fits: 6.6L V8 DIESEL Turbocharged | AXBUCHGM3 | 🇺🇸 US 🇨🇦 CA | Rear View Camera Harness | View on Amazon |
This table covers the harness connectors at the Radio. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
2 Radio Connector parts for the 2021 GMC Sierra 2500 come from METRA.
Listed part numbers: METRA AXBUCHGM2 and METRA AXBUCHGM3.
Starter Solenoid Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2984 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the harness connectors at the Starter Solenoid. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S2984.
Temperature Sender / Sensor Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2860 | 🇺🇸 US 🇨🇦 CA | Connector Shape: OvalGauge: 16 Gauge | View on Amazon |
This table covers the harness connectors at the Temperature Sender / Sensor. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S2860.
Throttle Control Actuator Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2409 | 🇺🇸 US 🇨🇦 CA | Gender: MaleHarness Length | View on Amazon |
This table covers the harness connectors at the Throttle Control Actuator. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S2409.
Trailer Adapter Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 57101 | 🇺🇸 US 🇨🇦 CA | 7-Way Round RV To 4-Way Flat Adapter | View on Amazon |
This table covers the harness connectors at the Trailer Adapter. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — CURT 57101.
Trailer Brake Switch Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 51525 | 🇺🇸 US 🇨🇦 CA | Brake Control Adapter Harness | View on Amazon |
| TEKONSHA Fits: 6.6L V8 DIESEL Turbocharged | 3064 | 🇺🇸 US 🇨🇦 CA | 2-Plug Harness (Plugs Directly Into Your Vehicle and Brake Control)Brake Control Wiring Adapter | View on Amazon |
This table covers the harness connectors at the Trailer Brake Switch. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
2 Trailer Brake Switch Connector parts are listed for the 2021 GMC Sierra 2500, from CURT and TEKONSHA.
Listed part numbers: CURT 51525 and TEKONSHA 3064.
Trailer Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CURT Popular Fits: 6.6L V8 DIESEL Turbocharged | 55415 | 🇺🇸 US 🇨🇦 CA | Replacement 7-Way RV Blade OEM Socket | View on Amazon |
| CURT Popular Fits: 6.6L V8 DIESEL Turbocharged | 56229 | 🇺🇸 US 🇨🇦 CA | 7-Way USCAR Electrical ConnectorLength: 24 in. | View on Amazon |
| STANDARD MOTOR PRODUCTS Popular Fits: 6.6L V8 DIESEL Turbocharged | TC656 | 🇺🇸 US 🇨🇦 CA | with Towing PackageOE Style | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56415 | 🇺🇸 US 🇨🇦 CA | Replacement 7-Way RV Blade OEM SocketTwist-In | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 55515 | 🇺🇸 US 🇨🇦 CA | Custom Wiring ConnectorOE 4-Way Flat | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56515 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Connector5-Way Flat | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 55774 | 🇺🇸 US 🇨🇦 CA | OEM Vehicle to Trailer Connector with Harness7-Way and 4-Way | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 57015 | 🇺🇸 US 🇨🇦 CA | OEM Replacement Dual-Output 7 and 4 Way ConnectorPlugs Into USCAR Socket | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 55384 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Connector4-Way Flat | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 57020 | 🇺🇸 US 🇨🇦 CA | OEM Replacement Dual-Output 7 and 4 Way ConnectorPackaged | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56584 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Harness5-Way Flat | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 58984 | 🇺🇸 US 🇨🇦 CA | 4WD | View on Amazon |
| DORMAN Fits: 6.6L V8 DIESEL Turbocharged | 645170 | 🇺🇸 US 🇨🇦 CA | Black | View on Amazon |
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | TC654 | 🇺🇸 US 🇨🇦 CA | with Towing Packagewith 7 Way | View on Amazon |
This table covers the trailer-lighting connectors at the hitch. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
14 Trailer Connector parts for the 2021 GMC Sierra 2500 come from 3 brands — CURT, STANDARD MOTOR PRODUCTS and DORMAN. The "Popular" part is CURT 55415.
Trailer Extension Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56475 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Harness Extension | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56003 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Harness Extension | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56072 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Harness ExtensionLength: 7ft. | View on Amazon |
| CURT Fits: 6.6L V8 DIESEL Turbocharged | 56000010 | 🇺🇸 US 🇨🇦 CA | Custom Wiring Harness ExtensionPack of 10 | View on Amazon |
This table covers the harness connectors at the Trailer Extension. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
CURT supplies the 4 Trailer Extension Connector parts for the 2021 GMC Sierra 2500.
This group includes CURT 56475, CURT 56003 and CURT 56072 and the remaining parts above.
Transmission-Automatic Wiring Harness / Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 24051935 | 🇺🇸 US 🇨🇦 CA | End 2 Terminal Gender: Male Female | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 24297666 | 🇺🇸 US 🇨🇦 CA | 10 speed Automatic trans. | View on Amazon |
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 24045624 | 🇺🇸 US 🇨🇦 CA | End 2 Terminal Gender: Female | View on Amazon |
This table covers the wiring-harness connectors at the Transmission-Automatic. Typical signs include an intermittent fault that moves when you wiggle the harness, or a melted or corroded plug. Match terminal count and keyway. Repair with heat-shrink terminals, not twist-and-tape.
3 Transmission-Automatic Wiring Harness / Connector parts for the 2021 GMC Sierra 2500 come from GM GENUINE.
Part numbers include GM GENUINE 24051935, GM GENUINE 24297666 and GM GENUINE 24045624.
Washer Pump Connector
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| STANDARD MOTOR PRODUCTS Fits: 6.6L V8 DIESEL Turbocharged | S2279 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the harness connectors at the Washer Pump. Typical signs include an intermittent fault that moves when you wiggle the plug, green corrosion, or a melted housing. Match terminal count and keyway, not just color. Many families look identical and will not lock.
One part is listed for the 2021 GMC Sierra 2500 — STANDARD MOTOR PRODUCTS S2279.
Wire Terminal
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: 6.6L V8 DIESEL Turbocharged | 85528055 | 🇺🇸 US 🇨🇦 CA | Multi-PurposeColor: White | View on Amazon |
This table covers the terminals crimped onto a harness lead.
One part is listed for the 2021 GMC Sierra 2500 — GM GENUINE 85528055.
Buying Electrical Connector Parts for a 2021 GMC Sierra 2500
On this vehicle, the connector system supplies the pigtails and connector bodies that terminate the vehicle harness at lamps, sensors and modules.
- Match the engine first. Every electrical connector part here is engine-specific; each row shows which engine(s) it fits.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, use heat-shrink crimp connectors rather than twist-and-tape for any pigtail splice, especially outside the cabin.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Trailer Connector and Chassis Wiring Harness / Connector .
Frequently Asked Questions
How many electrical connector parts fit the 2021 GMC Sierra 2500?
Our catalog currently lists 74 electrical connector parts for the 2021 GMC Sierra 2500 across 37 subcategories and 11 brands, covering both the 6.6L V8 and the 6.6L V8 DIESEL Turbocharged. Each part is matched to the engine(s) it fits.
Do electrical connector parts differ between 2021 GMC Sierra 2500 engines?
Yes. Every electrical connector part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of electrical connector problems on a 2021 GMC Sierra 2500?
Common symptoms include intermittent faults that move when the harness is wiggled, green corrosion inside a plug, or melted connector housings near heat sources. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, use heat-shrink crimp connectors rather than twist-and-tape for any pigtail splice, especially outside the cabin.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 GMC Sierra 2500 was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 GMC Sierra 2500?
First match the engine — each row shows which engine(s) the part fits. Then match the connector by terminal count and keyway, not just appearance — many families look identical but will not lock. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 GMC Sierra 2500
Electrical Connector Parts for Other GMC Sierra 2500 Years
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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.