Caprice Wagon V8-350 5.7L (1994)
Twilight Sentinel: Testing and Inspection
Troubleshooting Hints
PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS:
1. Check LO Beam Headlamps and HI Beam Headlamps for damage to the filament or bulb.
CAUTION: Halogen bulbs contain a gas under pressure. Handling a bulb improperly could cause it to shatter into flying glass fragments.
To help avoid personal injury:
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Turn the Lamp Switch to "OFF" and allow bulb to cool before changing bulbs. Leave the switch in "OFF" until bulb change is
complete.
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Always wear eye protection when changing a halogen bulb.
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Handle the bulb only by its base. Avoid touching the glass.
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Do not drop or scratch the bulb. Keep moisture away.
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Place the used bulb in the new bulb's carton and dispose of it properly. Keep halogen bulbs out of reach of children.
2. Check I/P Fuse #31 for open. If open, check for short to ground in CKT 240.
3. Check I/P Fuse #13 for open. If open, check for short to ground in CKT 639.
4. Check that grounds G102, G106, G200 and G202 are clean and tight.
5. Check that the Headlamp Auto Control Ambient Light Sensor is not obstructed.
6. If Headlights on one side are dimly lit, check the ground on that side.
7. If HI Beam Headlights do not light, but the HI Beam Indicator lights, check LT GRN (11) wire for an open.
8. If one Headlamp doesn't work, check the connections, Headlamp and the wires to the Headlamp.
9. If either the Headlights or the Park Lights, but not both, will not turn "OFF," disconnect Headlamp Auto Control Module.
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If lights go "OFF," replace the Headlamp Auto Control Module.
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If lights don't go "OFF," replace the Headlamp Switch.
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Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a
continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded checked by monitoring for a
voltage drop with the system operational (under load).
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Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems refer Diagnostic Aids. See:
Diagrams/Diagnostic Aids
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Refer to System Diagnosis. See: System Diagnosis
System Diagnosis
Perform the System Check in the order shown. When a fault is found, refer to the Symptom Table for the appropriate diagnostic procedure(s). If a
normal result is found at each and every step of the System Check, the fault may be intermittent. See: System Check See: Symptom Table
To help isolate an intermittent fault, first examine the mating terminals at each component and connector for a poor connection. Also check that each
terminal of mating connectors is properly seated in the connector body. If the connections appear to be reliable, try the System Check again while
moving the wiring harness from side to side at each component and in-line connector, to try and induce the intermittent fault.
Once a fault has been corrected, perform the System Check to verify the diagnosis.
