High Intensity Discharge Lamp Malfunction
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High Intensity Discharge Lamp Malfunction
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Headlamp Low Beam Relay B+
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B258A 04
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B258A 04
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-
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-
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Headlamp Low Beam Relay Control
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B258A 02
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B258A 04
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B258A 01
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-
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Left Low Beam Headlamp Control
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2
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2
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1
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-
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Right Low Beam Headlamp Control
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2
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2
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1
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-
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1. Headlamps Always ON
2. Headlamps Always OFF
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Circuit/System Description
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When the headlight switch is placed in low beam position, the body control module (BCM) energizes the low beam headlamp relay which supplies battery voltage to the respective headlamp control circuits.
The following symptoms are noticeable signs of bulb failure:
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Flickering light, caused in the early stages of bulb failure.
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Lights go out, caused when the ballast detects excessive, repetitive bulb re-strike.
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Color change-The lamp may change to a dim pink glow.
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Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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Ignition ON, command the Headlamp Low Beam ON and OFF with a scan tool. The E4G headlamp-left low beam and the E4H headlamp-right low beam should turn ON and OFF when changing between the commanded states.
Warning
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The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:
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Never open the high intensity discharge system ballast or the arc tube assembly starter.
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Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.
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1.
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Ignition OFF, disconnect the KR49 headlamp low beam relay.
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2.
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Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.
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3.
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If the test lamp illuminates, test the control circuit for a short to voltage.
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4.
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Verify that a test lamp illuminates between the B+ circuit terminal 87 and ground.
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5.
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If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance
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6.
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Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.
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7.
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If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
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8.
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Connect a 20 A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the E4G headlamp-left low beam and the E4H headlamp-right low beam are activated.
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9.
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If the E4G headlamp-left low beam or the E4H headlamp-right low beam do not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the appropriate E4 headlamp-low beam
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10.
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Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
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11.
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Ignition ON, command the low beam lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
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12.
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If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
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13.
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If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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14.
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If all circuits test normal, test or replace the KR49 headlamp low beam relay.
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Relay Test
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1.
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Ignition OFF, disconnect the KR49 headlamp low beam relay.
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2.
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Test for 60-180 Ω between terminals 85 and 86.
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3.
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If not within the specified range, replace the KR49 headlamp low beam relay.
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4.
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Test for infinite resistance between the following terminals:
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5.
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If not the specified value, replace the KR49 headlamp low beam relay.
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6.
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Install a 15A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.
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7.
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If greater than the specified range, replace the KR49 headlamp low beam relay.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
