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 MANUALSGMC1998ENVOY 2WD V6-4.3L VIN WREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSBODY CONTROL MODULETESTING AND INSPECTIONSCAN TOOL TESTING AND PROCEDURESSCAN TOOL DATA DEFINITIONSDATAAMBIENT LIGHT
1998 GMC Envoy 2WD V6-4.3L VIN W
Ambient Light
1998 GMC Envoy 2WD V6-4.3L VIN WSECTION Ambient Light
Data:
Range: Light/Dark
The displayed value refers to the amount of ambient light level calculated by the BCM using the light sensor.
The information is used by the BCM for operation of the following features:
^ The automatic headlamp feature
^ The daytime running lamps (DRL) feature The BCM supplies 5 volts to the ambient light photocell sensor and receives a return signal voltage from the ambient light photocell sensor on the return signal circuit.
The following actions will occur if there is an open or a short to ground in the ambient light sensor circuit:
^ The scan tool will display DARK.
^ The BCM will default into a DARK state and turn the headlamps ON.
If the headlamps are set to the AUTO position while in the LIGHT state and the ambient light level conditions change to DARK for 15 seconds, the BCM will turn the headlamps ON.
If the headlamps are set to the AUTO position while the DARK state and the ambient light level conditions change to LIGHT for 20 seconds, the BCM will turn the headlamps OFF.
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.