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 MANAGEMENTRELAYS AND MODULES - POWERTRAIN MANAGEMENTRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSBODY CONTROL MODULEDESCRIPTION AND OPERATIONBODY CONTROL SYSTEM CIRCUIT DESCRIPTIONAMBIENT LEVEL SENSOR
1998 GMC Envoy 2WD V6-4.3L VIN W
Ambient Level Sensor
1998 GMC Envoy 2WD V6-4.3L VIN WSECTION Ambient Level Sensor
The ambient light level sensor has the following 2 states:
^ The LIGHT state
^ The DARK state
If the headlamp switch is set to AUTO while in the LIGHT state, the following components will stay fully bright:
^ The radio
^ The PRNDL
^ The 4-wheel drive switch
^ The overhead console
^ The radio
^ The PRNDL
^ The 4-wheel drive switch
^ The overhead console
^ The radio
^ The PRNDL
^ The 4-wheel drive switch
^ The overhead console
The above components will STEP dim with the dimming control when the headlamp switch is set to one of the following positions while in the LIGHT state:
^ PARK LAMP
^ HEADLAMP
The above components will STEP dim with the dimming control when the headlamp switch is set to one of the following positions while in the DARK state:
^ AUTO
^ PARK LAMP
^ HEADLAMP
^ The LIGHT state
^ The DARK state
If the headlamp switch is set to AUTO while in the LIGHT state, the following components will stay fully bright:
^ The radio
^ The PRNDL
^ The 4-wheel drive switch
^ The overhead console
^ The radio
^ The PRNDL
^ The 4-wheel drive switch
^ The overhead console
^ The radio
^ The PRNDL
^ The 4-wheel drive switch
^ The overhead console
The above components will STEP dim with the dimming control when the headlamp switch is set to one of the following positions while in the LIGHT state:
^ PARK LAMP
^ HEADLAMP
The above components will STEP dim with the dimming control when the headlamp switch is set to one of the following positions while in the DARK state:
^ AUTO
^ PARK LAMP
^ HEADLAMP
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.