The Chevrolet Express (2003-2022) is a full-size van widely used for commercial and passenger purposes. Its electrical system is essential for managing both critical vehicle operations and comfort features, with the fuse box and relays serving as key components in ensuring smooth functionality.
The fuse box in the Chevrolet Express is typically located in the engine compartment and inside the cabin, usually under the dashboard on the driver’s side. The engine compartment fuse box protects high-power circuits such as the engine, transmission, and ABS, while the interior fuse box manages lower-power systems like the radio, power windows, and interior lighting. Each fuse prevents potential electrical damage by breaking the connection during overloads or short circuits.
Relays in the Express are responsible for controlling high-current systems like the fuel pump, starter motor, and cooling fans. These relays act as switches, allowing low-current systems to control high-power operations safely. Regular maintenance and inspection of both the fuses and relays are crucial to preventing electrical failures and ensuring the Express operates reliably, whether it’s for transporting passengers or hauling cargo.
MUST READ: DYI – How to Check Car Fuses?
(2003-2022) Chevrolet Express fuse box and relay with Diagram
WARNING
- Never replace a fuse with one that has a higher amperage rating.
- A fuse with a too-high amperage could damage the electrical part and cause a fire.
- On no account should fuses be repaired (e.g. patched up with tin foil or wire) as this may cause serious damage elsewhere in the electrical circuit or cause a fire.
- If a fuse blows repeatedly, do not keep replacing it. Instead, have the cause for the repeated short circuit or overload tracked and fixed.
- Terminal and harness assignments for individual connectors will vary depending on vehicle equipment level, model, and market.
Chevrolet Express (2003-2022) fuse assignment
- Cigar lighter (power outlet) fuses in the Chevrolet Express are located in the Engine Compartment Fuse Box. 2003-2007 – see fuses № 29 (Auxiliary Power Outlets) and №30 (Cigarette Lighter). 2008-2009 see fuses №33 (Auxiliary Power Outlet) and №38 (Cigarette Lighter). 2010-2022 – see fuses №25 (Auxiliary Power Outlet) and №73 (Cigarette Lighter).
Year of production: from 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022
Fuse box location
Floor Console Fuse Box
It is located under the driver’s seat.
Engine Compartment
It is located on the driver’s side of the engine compartment.
Fuse box diagrams
2003, 2004, 2005, 2006, 2007
Floor Console Fuse Box
Assignment of the fuses and relay in the Floor Console Fuse Box (2003-2007)
| № | Usage |
|---|---|
| 1 | Spare |
| 2 | Outside Rear View Mirror |
| 3 | Courtesy Lamp/SEO |
| 4 | Left Rear Stop/Turn Signal |
| 5 | Cargo Locks |
| 6 | Right Rear Stop/Turn Signal |
| 7 | Driver Locks |
| 8 | Stop/Center High Mounted Stop Lamp |
| 9 | Climate Control 1 |
| 10 | Climate Control |
| 11 | Brakes |
| 12 | Heated Mirror/Defogger |
| 13 | Right Rear Blower |
| 14 | Driver Turn Mirror |
| 15 | Door Locks |
| 16 | Upfitter Park |
| 17 | Not Available |
| 18 | Left Rear Park Lamp |
| 19 | Pass Turn Mirror |
| 20 | Right Rear Park Lamp |
| 21 | Trailer Park Lamp |
| 22 | Front Park Lamp |
| 32 | Auxilary 1 |
| 33 | Auxilary 2 |
| Circuit Breaker | |
| 34 | Power Window |
| Relays | |
| 23 | Window Residual Accessory Power |
| 24 | Auxiliary |
| 25 | Right Rear Defogger |
| 26 | Courtesy Lamp |
| 27 | Cargo Unlock |
| 28 | Driver Unlock |
| 29 | Park Lamp |
| 30 | Door Locks |
| 31 | Passenger Unlock |
Engine Compartment
Assignment of the fuses and relay in the Engine Compartment (2003-2007)
| № | Usage |
|---|---|
| 1 | Radio Battery |
| 2 | Gasoline: Powertrain Control Module Battery Diesel: FOH, Engine Control Module, Transmission Control Module Battery |
| 3 | Left Rear Turn Lamp |
| 4 | Right Rear Turn Lamp |
| 5 | Backup Lamps Trailer Wiring |
| 6 | Ignition 0 |
| 7 | Stop Lamp |
| 8 | Right Rear Defogger/Heated Mirror |
| 9 | Right Daytime Running Lamp/Turn Signal |
| 10 | Left Daytime Running Lamp/Turn Signal |
| 11 | Truck Body Control Module 4 |
| 12 | Fuel Pump |
| 13 | Trailer |
| 14 | Hazard Flashers |
| 15 | Horn |
| 16 | Truck Body Control Module 3 |
| 17 | Trailer Stop/Turn Signal |
| 18 | Truck Body Control Module 2 |
| 19 | Truck Body Control Module |
| 20 | Remote Function Actuator |
| 21 | Gasoline: Engine 2 Diesel: Spare |
| 22 | Ignition E |
| 23 | Engine 1 |
| 24 | Truck Body Control Module Ignition 1 |
| 25 | Gasoline: Spare Diesel: Fuel Heater |
| 26 | Inside Rearview Mirror |
| 27 | Crankcase |
| 28 | Brake Transmission Shift Interlock System |
| 29 | Auxiliary Power Outlets |
| 30 | Cigarette Lighter |
| 31 | Instrument Panel Cluster |
| 32 | Air Conditioning |
| 33 | Gasoline: Spare Diesel: Engine Control Module |
| 34 | Gasoline: Canister Vent Solenoid Diesel: Rear Fog Lamps |
| 35 | Spare |
| 36 | Brake Transmission Shift Interlock, Vehicle Back-Up |
| 37 | Airbag |
| 38 | Gasoline: Powertrain Control Module Ignition 1 Diesel: Engine Control Module, Transmission Control Module, Glow Plug Control Module Ignition 1 |
| 39 | Gasoline: Oxygen Sensor B Diesel: Spare |
| 40 | Oxygen Sensor A |
| 41 | Windshield Wipers |
| 42 | Right Headlamp – Low Beam |
| 43 | Left Headlamp – Low Beam |
| 44 | Left Headlamp – High Beam |
| 45 | Right Headlamp – High Beam |
| 46 | Gasoline: Truck Body Controller- Accessory Diesel: Truck Body Controller, Transmission Control Module Accessory |
| 47 | Front Windshield Wiper |
| 48 | Anti-lock Brakes, Vehicle Stability Enhancement System |
| 49 | Ignition A |
| 50 | Trailer |
| 51 | Climate Control Blower |
| 52 | Ignition B |
| 63 | Gasoline: Spare Diesel: Engine Control Module Actuator |
| 64 | Spare |
| Relays | |
| 53 | Windshield Wiper |
| 54 | Air Conditioning |
| 55 | Gasoline: Spare Diesel: Rear Fog Lamps |
| 56 | Headlamp – High Beam |
| 57 | Fuel Pump |
| 58 | Headlamp – Low Beam |
| 59 | Horn |
| 62 / SPARE (G), ECM (D) | Gasoline: Spare Diesel: Engine Control Module |
| 61 / STRTR | Starter |
| Circuit Breaker | |
| 60 / PWR SEAT | 2003-2005: Power Window (#60) 2006-2007: Power Seat |
2008, 2009
Floor Console Fuse Box
Assignment of the fuses and relay in the Floor Console Fuse Box (2008, 2009)
| № | Usage |
|---|---|
| 1 | Climate Control 2 (HVAC) |
| 2 | Compass |
| 3 | Ignition Switch, Theft Deterrent System Module (PK3) |
| 4 | Upfitter Courtesy Lamps |
| 5 | Climate Control 1 (HVAC) |
| 6 | Empty |
| 7 | Instrument Panel Cluster |
| 8 | Audio System, Chime |
| 9 | Auxiliary Park Lamp |
| 10 | Auxiliary Trailer Back-up Lamps |
| 11 | Remote Function Actuator, Tire Pressure Monitor (TPM) |
| 12 | Climate Control (HVAC) Controls |
| 13 | Trailer Park Lamps |
| 14 | Front Park Lamps |
| 15 | Taillamps, Back-up Lamps |
| 16 | Empty |
| 17 | Steering Wheel Sensor |
| 18 | Outside Rearview Mirror Switch |
| 19 | Empty |
| 20 | Empty |
| 21 | Rear Defogger |
| 22 | Outside Rearview Mirror Heater |
| 23 | Empty |
| 24 | Empty |
| 25 | Cargo Door Unlock |
| 26 | Rear Door Lock |
| 27 | Front Door Lock |
| 28 | Rear Passenger Door Unlock |
| 29 | Upfitter Park Lamps |
| 30 | Front Passenger Door Unlock |
| 31 | Driver Door Unlock |
| 32 | Airbag System, Automatic Occupant Sensing (AOS) System |
| 33 | Right Rear Park Lamp |
| 34 | Left Rear Park Lamp |
| 35 | Upfitter Auxiliary 2 (J-Case) |
| 36 | Upfitter Auxiliary 1 (J-Case) |
| 37 | Rear Blower (J-Case) |
| 38 | Empty (J-Case) |
| 39 | Run (High Current Micro) |
| 40 | Park Lamps (High Current Micro) |
| 41 | Empty (Mini Micro) |
| 42 | Upfitter Auxiliary 2 (High Current ISO Relay) |
| 43 | Retained Accessory Power (RAP) (High Current Micro) |
| 44 | Rear Defogger (High Current Micro) |
| Circuit Breaker | |
| 45 | Power Window |
| 46 | Power Seats |
Engine Compartment
Assignment of the fuses and relay in the Engine Compartment (2008, 2009)
| № | Usage |
|---|---|
| 1 | Left High-Beam Headlamp |
| 2 | Fuel Pump |
| 3 | Empty |
| 4 | Diesel: Fuel Heater |
| 5 | Right High-Beam Headlamp |
| 6 | Empty |
| 7 | Left Low-Beam Headlamp |
| 8 | Right Stoplamp, Trailer Turn Signal |
| 9 | Right Low-Beam Headlamp |
| 10 | Daytime Running Lamps 2 (DRL) |
| 11 | Gasoline: Fuel System Control Module Ignition |
| 12 | Daytime Running Lamps 1 (DRL) |
| 13 | Auxiliary Stoplamp |
| 14 | Diesel: Fuel Operated Heater Module |
| 15 | Gasoline: Fuel System Control Module Battery |
| 16 | Left Stoplamp, Trailer Turn Signal |
| 17 | Gasoline: Canister Vent Solenoid |
| 18 | Empty |
| 19 | Empty |
| 20 | Body Control Module 1 |
| 21 | Special Equipment Option (SEO) |
| 22 | Body Control Module 4 |
| 23 | Body Control Module 6 |
| 24 | Empty |
| 25 | Body Control Module 7 |
| 26 | Body Control Module 3 |
| 27 | Body Control Module 5 |
| 28 | Empty |
| 29 | Empty |
| 30 | Instrument Panel Cluster |
| 31 | Empty |
| 32 | Brake Switch |
| 33 | Auxiliary Power Outlet |
| 34 | Airbag |
| 35 | Trailer Wiring |
| 36 | Gasoline: Steering Wheel Sensor |
| 37 | Body Control Module 2 |
| 38 | Cigarette Lighter, Data Link Controller |
| 39 | Windshield Wiper |
| 40 | Empty |
| 41 | Windshield Washer |
| 42 | Empty |
| 43 | Horn |
| 44 | Transmission Control Module Battery |
| 45 | Empty |
| 46 | Gasoline: Oxygen Sensor 1 |
| 47 | Transmission Control Module Ignition |
| 48 | Engine Control Module Ignition |
| 49 | Mass Airflow Sensor, Canister Vent |
| 50 | Engine Control Module, Powertrain |
| 51 | Transmission |
| 52 | Gasoline: Even Ignition Injectors |
| 53 | Diesel: Glow Plug Module |
| 54 | Engine Control Module Battery |
| 55 | Gasoline: Odd Ignition Injectors |
| 56 | Gasoline: Oxygen Sensor 2 |
| 57 | Air Conditioning Compressor |
| 58 | Diesel: Fan Clutch |
| 59 | Gasoline: V6 Fuel Injectors |
| 60 | Antilock Brake System Module (J-Case) |
| 61 | Antilock Brake System Motor (J-Case) |
| 62 | Trailer Wiring (J-Case) |
| 63 | Empty |
| 64 | Starter Solenoid (J-Case) |
| 65 | Diesel: Engine Control Module (ECM), Powertrain (J-Case) |
| 66 | Front Blower (J-Case) |
| 67 | Empty |
| 77 | Body BEC (Mega Fuse) |
| Relays | |
| 68 | Empty |
| 69 | Run, Crank (High Current Micro) |
| 70 | Windshield Wiper High (High Current Micro) |
| 71 | Windshield Wiper (High Current Micro) |
| 72 | Fuel Pump (Mini Micro) |
| 73 | Crank (High Current Micro) |
| 74 | Air Conditioning Compressor (Mini Micro) |
| 75 | Fan Clutch (Solid State) |
| 76 | Powertrain (High Current Micro) |
2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, and 2022
Floor Console Fuse Box
Assignment of the fuses and relay in the Floor Console Fuse Box (2010-2022)
| № | Usage |
|---|---|
| F1 | — |
| F2 | Steering Wheel Sensor |
| F3 | Auxiliary Parking Lamps |
| F4 | Front Park Lamps |
| F5 | Trailer Park Lamps |
| F6 | Upfitter/Parking lamps |
| F7 | Right Rear Park Lamp |
| F8 | Left Rear Park Lamp |
| F9 | Exterior rearview mirror switch 2019-2022: Exterior rear mirror switch/ Door lock-unlock control upfitter/Front camera module |
| F10 | Airbag/Automatic occupant sensing |
| F11 | OnStar (If Equipped) |
| F12 | Door lock/unlock control upfitter (if equipped) 2019-2020: ECM batt V6 gas |
| F13 | Heating, Ventilation and Air Conditioning 2 |
| F14 | Heating, Ventilation and Air Conditioning 1 |
| F15 | 2010-2019: Not Used. 2020-2022: Reflected LED display |
| F16 | Upfitter aux 1 / Gas ambulance |
| F17 | Exterior rearview heated mirrors |
| F18 | Rear Window Defogger |
| F19 | Compass |
| F20 | Radio/Chime/ SiriusXM satellite radio |
| F21 | Remote Function Actuator/Tire Pressure Monitor |
| F22 | Ignition Switch/Discrete Logic Ignition Sensor |
| F23 | Instrument Cluster |
| F24 | — |
| F25 | Heating, Ventilation and Air Conditioning control |
| F26 | Auxiliary/Trailer reverse lamps |
| F27 | Reverse lamps |
| F28 | Upfitter 2 / Reading lamps / Ambulance |
| F29 | Rear blower |
| F30 | Upfitter/Courtesy Lamps |
| F31 | Front Door Lock |
| F32 | Rear Door Lock |
| F33 | Cargo Door Unlock |
| F34 | Passenger Door Unlock |
| F35 | Rear Passenger Door Unlock |
| F36 | Driver Door Unlock |
| F37 | Empty |
| F38 | — |
| Relays | |
| K1 | Run (High Current Micro) |
| K2 | Empty (High Current Micro) |
| K3 | Park Lamps (High Current Micro) |
| K4 | Upfitter Auxiliary 2 (High Current Mini) |
| K5 | Rear Defogger (High Current Micro) |
| K6 | Retained Accessory Power (RAP) (High Current Micro) |
| Circuit Breaker | |
| CB1 | Power Seats |
| CB2 | Power Windows |
Engine Compartment
Assignment of the fuses and relay in the Engine Compartment (2010-2022)
| № | Usage |
|---|---|
| 1 | ABS motor |
| 2 | ABS module |
| 3 | Right trailer stoplamp/Turnlamp |
| 4 | — |
| 5 | — |
| 6 | Fuel system control module/Ignition |
| 7 | Body Control Module 5 |
| 8 | Body Control Module 7 |
| 9 | Body Control Module 4 |
| 10 | Instrument cluster |
| 11 | Trailer Wiring |
| 12 | 2010-2016, 2018-2022: Not Used 2017: Interior rear vision camera module |
| 13 | 2010-2016: Brake Switch 2017: Not Used 2018-2022: Interior rear vision camera module |
| 14 | Windshield Washer |
| 16 | Horn |
| 17 | Transmission |
| 18 | A/C |
| 19 | Engine control module battery |
| 20 | 2018-2019: Cutaway/Left stoplamp/Turnlamp. 2020-2022: Left stop/turn cutaway lamp |
| 21 | Left trailer stoplamp/Turnlamp |
| 22 | 2018-2019: Cutaway/Right stoplamp/Turnlamp. 2020-2022: Left stop/turn trailer lamp |
| 23 | 2021-2022: NOX Sensor (Diesel Only) |
| 24 | Fuel Pump |
| 25 | Auxiliary Power Outlet |
| 26 | Body Control Module 3 |
| 27 | Special Equipment Option |
| 28 | Airbag |
| 29 | Steering Wheel Sensor |
| 30 | Engine control module Ignition/Glow Plug Module |
| 31 | Transmission control module/Ignition |
| 32 | Transmission control module 1 battery/Engine control module battery power (gas 6 cyl) |
| 33 | 2017-2022: Rear parking aid module |
| 34 | 2021-2022: NOX Sensor (Diesel Only) |
| 35 | 2010-2017: Fuel Operated Heater Module 2018-2020: Not Used 2021-2022: Fuel Heater Control Module (Diesel Only |
| 36 | Fuel System Control Module Battery |
| 41 | 2018-2020: Transmission control 2 module battery power |
| 42 | Trailer wiring |
| 43 | 2010-2016: Fan High 2017: EV fan clutch 2018-2020: Not Used 2021-2022: Electro Viscous Fan Clutch (Diesel Only) |
| 44 | Starter solenoid |
| 45 | Engine control module/Powertrain |
| 46 | 2010-2016: Fuel System Control Module Battery 2017: Not Used 2018-2022: AC DC inverter |
| 47 | Cooling fan – low |
| 51 | Left high-beam headlamp |
| 52 | Right high-beam headlamp |
| 53 | Left low-beam headlamp |
| 54 | Right low-beam headlamp |
| 55 | Wipers |
| 56 | Canister Vent Solenoid |
| 58 | Body Control Module 2 |
| 59 | Body Control Module 1 |
| 61 | 2010-2017: Not Used 2018-2022: Engine oil solenoid / Crankcase Vent Heater (Diesel Only) |
| 62 | O2 sensor 2 / EV fan (diesel) |
| 63 | — |
| 64 | Mass Air Flow/Canister Vent |
| 65 | Ignition/Injectors – odd |
| 66 | Daytime Running Lamps 2 |
| 67 | Daytime Running Lamps 1 |
| 68 | Auxiliary Stop Lamps |
| 69 | 2010-2016: Not Used 2017: Trailer stoplamps 2018-2022: External power for trailer |
| 70 | 2018-2020: Upfitter stoplamps |
| 71 | Fuel heater/Flex fuel sensor |
| 72 | Body Control Module 6 |
| 73 | Lighter/Data Link Connection |
| 74 | Front blower |
| 75 | V6 fuel injectors / Engine control module diesel |
| 76 | 2021-2022: Soot Sensors (Diesel Only) |
| 77 | O2 sensor 1 |
| 78 | Engine control module/Powertrain |
| 79 | Ignition/Injectors – even |
| Relays | |
| 15 | Run/Crank |
| 37 | 2021-2022: NOX Sensor (Diesel Only) |
| 38 | Fuel Pump |
| 39 | Crank |
| 40 | A/C Compressor |
| 48 | 2010-2016: Fan High 2017: EV fan clutch 2018-2020: Not Used 2021-2022: Electro Viscous Fan Clutch (Diesel Only) |
| 49 | Powertrain |
| 50 | 2010: Fan Clutch (EV) 2011-2020: Not Used |
| 57 | Cooling fan – low / Not Used |
| 60 | Fan Control / Not Used |
Auxiliary Fuse Block (2018-2022)
This block is located near the fuse box in the engine compartment.
| Fuses | Usage |
|---|---|
| MR-1 | Upfitter 1 |
| MR-2 | Upfitter 2 |
| MR-3 | Upfitter power control |
| Relays: | |
| MR Rel 1 | Upfitter 1 |
| MR Rel 2 | Upfitter 1 |
Mega Fuse Holder (2018-2021) – Starter motor
Conclusion
For owners and enthusiasts of classic Chevrolet Express (2003-2022), understanding the fuse box and relay systems is essential for vehicle maintenance. Regular inspection and maintenance of these components helped ensure the vehicle’s longevity and reliability, preserving its status as a symbol of Chevrolet’s craftsmanship and innovation in the automotive industry during that era.
