Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1673 (WIRING SYSTEMS (GENERAL INFORMATION))COMPONENT LOCATORELECTRICAL CENTER IDENTIFICATION VIEWSUNDERHOOD FUSE BLOCK LABEL
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Underhood Fuse Block Label
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Underhood Fuse Block Label
WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Underhood Fuse Block Label Usage
| Fuse | Rating | Description |
|---|---|---|
| FOG LAMP Relay | - | Fog Lamps |
| DRL Relay | - | DRL Resistor |
| HORN Relay | - | Horn |
| ECM/TCM Fuse | 10 A | ECM, TCM |
| HORN Fuse | 15 A | HORN Relay |
| EMISS Fuse | 10 A | Heated Oxygen Sensors, EVAP Purge Solenoid, EVAP Vent Solenoid, MAF Sensor (w/L81) |
| REAR DEFOG Fuse | 25 A | REAR DEFOG Relay |
| COOL FAN HIGH Relay (2003, Late 2002) | - | Cooling Fan |
| COOL FAN 1 Relay (Early 2002) | - | Cooling Fan |
| ENG MAIN Relay | - | EMISS Fuse, ETC Fuse (w/L61), INJ/MAN Fuse (w/L81), ECM/CAM Fuse (w/L81) |
| REAR DEFOG Relay | - | Rear Defogger Grid |
| FOG LP Fuse | 10 A | FOG LAMP Relay |
| LH HDLP Fuse | 15 A | Left High and Low Beam Headlamps |
| OIL RESET Switch | - | Oil Life Reset Switch |
| RH HDLP Fuse | 15 A | Right High and Low Beam Headlamps |
| A/C DIODE | - | - |
| WIPER SYSTEM Relay | - | FRT WIPER Fuse, RR WIPER Fuse |
| RR WIPER Fuse | 15 A | REAR WIPER Relay |
| FRT WIPER Fuse | 25 A | FRT WIPER Relay |
| ETC Fuse | 15 A | ECM |
| PWR WDW Relay | - | SUNROOF Fuse, Driver and Front Passenger Window Switches |
| ABS Fuse (w/ L81) | 10 A | EBCM |
| SUNROOF Fuse | 20 A | Sunroof Control Module |
| CIGAR/AUX 2 Fuse | 20 A | Auxiliary Power Outlet - Rear, Cigar Lighter |
| BRAKE Fuse | 15 A | Stop Lamp Switch |
| FRT WIPER Relay | - | Windshield Wiper Motor, Windshield Wiper/Washer Switch |
| COOL FAN LOW Relay (2003, Late 2002) | - | ECM |
| A/C CLUTCH Relay | - | A/C Compressor Clutch |
| ECM/CAM Fuse (L81) | 15 A | CMP Sensor, ECM |
| A/C CLUTCH Fuse | 10 A | A/C CLUTCH Relay |
| FUEL PUMP Fuse | 10 A | FUEL PUMP Relay |
| INJ/MANF Fuse (L81) | 15 A | Fuel Injectors, IMRC |
| IGN INJ Fuse (L61) | 15 A | Fuel Injectors, ICM |
| PWR TRAIN Fuse | 10 A | ECM, Automatic Transmission (w/A/T), PNP Switch (w/ L81), TCM (w/ L81) |
| BACKUP LAMP Relay | - | Not Used |
| AUX1OUTLET Fuse | 15 A | Auxiliary Power Outlet - Front (2002 Only) |
| BACKUP Fuse | 10 A | Backup Switch (w/ M/T), Coolant Level Switch, PNP Switch (w/ A/T), Wheel Speed Signal Conditioner Module (L81 w/o ABS), Vehicle Speed Sensor (w/ M/T) |
| FUEL PUMP Relay | - | Primary Fuel Pump and Sender Assembly |
| PREM AUD Fuse | 20 A | Amplifier (WBM w/ UR9/UP0) |
| HTD SEATS Fuse | 20 A | Driver and Front Passenger Heated Seat Modules |
| RR WIPER Relay | - | Rear Wiper Motor |
| ABS Fuse | 20 A | EBCM |
| BATT FEED Fuse | 40 A | I/P Fuse Block B+ Fuses |
| ABS PWR Fuse | 40 A | EBCM |
| ENG COOLING Fuse (Early 2002) | 25 A | COOLING FAN Relay |
| COOL FAN HIGH Fuse (2003, Late 2002) | 40 A | COOL FAN HIGH Relay |
| PWR WDW Fuse | 30 A | PWR WDW Relay |
| HVAC BLOWER Fuse | 40 A | HVAC Blower Motor |
| IGN Fuse | 30 A | Ignition Switch |
| COOL LO Fuse (2003, Late 2002 L61) | 20 A | ECM, Cooling Fan Resistor |
| COOL 2 Fuse (2003, Late 2002 L81) | 25 A | ECM, Cooling Fan Resistor |
| PWR SEAT Circuit Breaker | 30 A | Not Used |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.