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 1601 (BODY CONTROL SYSTEM)COMPONENT LOCATORBODY CONTROL SYSTEM CONNECTOR END VIEWS
2003 Chevrolet TrailBlazer 4.2 S, 4WD
Body Control System Connector End Views
2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Body Control System Connector End Views
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Body Control Module (BCM) Connector End View C1
| Connector Part Information |
|
||
|---|---|---|---|
| Pin | Wire Color | Circuit No. | Function |
| A1 | - | - | Not Used |
| A2 | WHT | 2282 | Headlamp Washer Relay Control (w/CE4) |
| A3 | ORN | 1140 | Battery Positive Voltage |
| A4 | BLK/WHT | 1969 | Headlamp High Beam Relay Control |
| A5 | PNK/WHT | 1970 | Headlamp Low Beam Relay Control |
| A6-A11 | - | - | Not Used |
| A12 | WHT | 278 | Ambient Light Sensor Signal |
| B1 | LT GRN | 1037 | BCM Class 2 Serial Data |
| B2 | BLK | 279 | Ambient Light Sensor Low Reference |
| B3 | LT GRN | 2270 | Rear Window Washer Relay Control |
| B4 | GRY/BLK | 2226 | Low Reference |
| B5 | GRY | 705 | 5 Volt Reference |
| B6 | WHT | 2283 | Rear Wiper/Washer Switch Supply Voltage |
| B7 | ORN/BLK | 2090 | Courtesy Lamps Supply Voltage |
| B8 | LT GRN | 1011 | Remote Radio Control Signal |
| B9 | GRY | 391 | Rear Window Wiper Switch Signal |
| B10 | YEL | 1836 | Security System Sensor Signal |
| B11 | GRY | 2521 | Right Sunload Sensor Signal |
| B12 | LT BLU/BLK | 2519 | Left Sunload Sensor Signal |
Body Control Module (BCM) Connector End View C2
| Connector Part Information |
|
||
|---|---|---|---|
| Pin | Wire Color | Circuit No. | Function |
| E1-E2 | - | - | Not Used |
| E3 | LT GRN | 80 | Key In Ignition Switch Signal |
| E4 | YEL | 307 | Headlamp Switch Flash to Pass Signal |
| E5 | GRY/BLK | 308 | Park Lamp Switch Signal |
| E6 | PNK/BLK | 109 | Hood Ajar Switch Signal (Export Only) |
| E7 | PNK | 1348 | Headlamp On Indicator Control |
| E8 | BLK | 1835 | Security System Sensor Low Reference |
| E9 | RED/WHT | 812 | 12 Volt Reference |
| E10 | - | - | Not Used |
| E11 | DK GRN/ WHT |
1317 | Fog Lamp Relay Control |
| E12 | BLK | 28 | Horn Relay Control |
| E13-E16 | - | - | Not Used |
| F1-F2 | - | - | Not Used |
| F3 | DK GRN | 113 | Windshield Wiper Switch Signal 2 |
| F4 | DK BLU/ WHT |
1495 | Courtesy Lamps On Signal |
| F5 | BRN/WHT | 1871 | Headlamp Washer Switch Signal (w/CE4) |
| F6 | ORN | 192 | Front Fog Lamp Switch Signal |
| F7 | LT BLU | 187 | Rear Fog Lamp Switch Signal |
| F8 | - | - | Not Used |
| F9 | WHT | 103 | Headlamp Switch Headlamps On Signal |
| F10 | LT GRN | 11 | Headlamp High Beam Supply Voltage |
| F11 | PPL | 328 | Interior Lamp Defeat Switch Signal |
| F12-F13 | - | - | Not Used |
| F14 | YEL | 710 | Class 2 Serial Data |
| F15-F16 | - | - | Not Used |
Body Control Module (BCM) Connector End View C3
| Connector Part Information |
|
||
|---|---|---|---|
| Pin | Wire Color | Circuit No. | Function |
| A1 | - | - | Battery Positive Voltage |
| A2 | - | - | Not Used |
| A3 | - | - | Right Rear Door Ajar Switch Signal |
| A4 | - | - | Park Brake Switch Signal |
| A5 | - | - | Door Lock Relay Control |
| A6 | - | - | Power Window Lockout Left Rear Control |
| A7 | - | - | Not Used |
| A8 | - | - | Left Rear Door Ajar Switch Signal |
| A9-A10 | - | - | Not Used |
| A11 | - | - | Ground |
| A12 | - | - | RAP Relay Supply Voltage |
| A13 | - | - | Door Unlock Relay Control |
| A14 | - | - | Park Lamp Relay Control |
| A15-A17 | - | - | Not Used |
| A18 | - | - | Ignition 0 Voltage |
| A19 | - | - | Battery Positive Voltage |
| A20 | - | - | Ignition 3 Voltage |
| B1 | - | - | Instrument Panel Lamps Dimming Control |
| B2 | - | - | Instrument Panel Lamps Dimming Control |
| B3 | - | - | Courtesy Lamp Supply Voltage |
| B4 | - | - | Battery Positive Voltage |
| B5 | - | - | Power Window Switch Right Rear Up Signal |
| B6 | - | - | Power Window Lockout Right Rear Control |
| B7 | - | - | Power Window Switch Right Rear Down Signal |
| B8 | - | - | Power Window Switch Left Rear Up Signal |
| B9 | - | - | Power Window Switch Left Rear Down Signal |
| B10 | - | - | Not Used |
| B11 | - | - | Ground |
| B12 | - | - | Backup Lamp Supply Voltage |
| B13 | - | - | Battery Positive Voltage |
| B14 | - | - | LED Dimming Supply |
| B15 | - | - | Accessory Voltage |
| B16 | - | - | Not Used |
| B17 | - | - | Battery Positive Voltage |
| B18 | - | - | Courtesy Lamps Supply Voltage |
| B19 | - | - | Rear Fog Lamp Relay and Indicator Control |
| B20 | - | - | Not Used |
RENDER: 1.0x
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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.