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High Intensity Discharge Lamp Malfunction




High Intensity Discharge Lamp Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

The vehicle headlamps are controlled by the body control module (BCM) based on inputs from the headlamp switch and the turn signal/multifunction switch. The headlamp switch has four positions: OFF, AUTOMATIC LIGHT, PARKING LIGHT, and LOW BEAM. The default headlamp switch position is AUTOMATIC LIGHT, in which the BCM uses the ambient light sensor to determine when headlamps are needed. The OFF portion of the headlamp switch is a momentary switch which overrides the automatic headlamp and will turn OFF the vehicle headlamps. When in the OFF position, the headlamp switch grounds the headlamp switch headlamps OFF signal circuit, prompting the BCM to turn OFF the headlamps. The Park position of the headlamp switch will only illuminate the vehicle parking lamps. The LOW BEAM position of the headlamp switch will illuminate both the parking lamps, as well has the headlamps. With the headlamp switch in the LOW BEAM position, the headlamp switch headlamps on signal circuit is grounded, prompting the BCM to turn on the headlamps, regardless of other factors such as ambient light.

When a low beam request is received, the BCM grounds the headlamp low beam relay control circuit. This energizes the coil in the headlamp low beam relay, causing the relay switch to close. This then applies B+ to both low beam high intensity discharge (HID) headlamps through the left low beam and right low beam fuses, illuminating the low beam headlamps. When a high beam request is received, the BCM grounds the headlamp high beam relay control circuit. This energizes the coil in the high beam relay, causing the relay switch to close. This then applies B+ to both low beam HID headlamps through the left high beam and right high beam fuses, illuminating the high beam headlamps.

Diagnostic Aids

The following symptoms are noticeable signs of bulb failure:

* Flickering light, caused in the early stages of bulb failure.
* Lights go out, caused when the ballast detects excessive, repetitive bulb re-strike.
* Color change-The lamp may change to a dim pink glow.

Reference Information
Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition ON, observe the function of the low beam headlamps while commanding the Low Beam Lamps 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 while changing between the commanded states.

• If the E4G headlamp-left low beam is always OFF, refer to Left Low Beam Inoperative

• If the E4H headlamp-right low beam is always OFF, refer to Right Low Beam Inoperative

• If both low beam headlamps are always ON or always OFF, refer to Low Beam Command Malfunction

2. Ignition ON, observe the function of the high beam headlamps while commanding the High Beam Lamps ON and OFF with a scan tool. The E4E headlamp-left high beam and the E4F headlamp-right high beam should turn ON and OFF while changing between the commanded states.

• If the E4E headlamp-left high beam is always OFF, refer to Left High Beam Inoperative

• If the E4F headlamp-right high beam is always OFF, refer to Right High Beam Inoperative

• If both high beam headlamps are always ON or always OFF, refer to High Beam Command Malfunction.

Circuit/System Testing

Warning

The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:

* Never open the high intensity discharge system ballast or the arc tube assembly starter.
* Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

Left Low Beam Inoperative
1. Ignition OFF, disconnect the X118 inline harness connector at the E13L headlamp-left.
2. Test for less than 30 ohm between the ground circuit harness connector terminal G and ground.

• If greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal A and ground.
4. Ignition ON, command the Low Beam Lamps ON with a scan tool, the test should illuminate while commanding the headlamp ON.

• If the test lamp does not illuminate and the circuit fuse is good, test the control circuit for an open/high resistance.

• If the test lamp does not illuminate and the circuit fuse is open, test the control circuit for a short to ground.

5. If all circuits test normal, replace the E4G headlamp-left low beam.

Right Low Beam Inoperative
1. Ignition OFF, disconnect the X120 inline harness connector at the E13R headlamp-right.
2. Test for less than 30 ohm between the ground circuit harness connector terminal G and ground.

• If greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal A and ground.
4. Ignition ON, command the Low Beam Lamps ON with a scan tool, the test should illuminate while commanding the headlamp ON.

• If the test lamp does not illuminate and the circuit fuse is good, test the control circuit for an open/high resistance.

• If the test lamp does not illuminate and the circuit fuse is open, test the control circuit for a short to ground.

5. If all circuits test normal, replace the E4H headlamp-right low beam.

Low Beam Command Malfunction
1. Ignition OFF, disconnect the KR49 headlamp low beam relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage

3. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.

• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

5. Connect a 15A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the E4G headlamp-left low beam and the E4H headlamp-right low beam are activated.

• If the E4G headlamp-left low beam and the E4H headlamp-right low beam do not activate, test the control circuit for a short to ground or an open/high resistance.

6. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
7. 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.

• 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.

• 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.

8. If all circuits test normal, test or replace the KR49 headlamp low beam relay.

Left High Beam Inoperative
1. Ignition OFF, disconnect the X118 inline harness connector at the E13L headlamp-left.
2. Test for less than 30 ohm between the ground circuit harness connector terminal J and ground.

• If greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal D and ground.
4. Ignition ON, command the High Beam Lamps ON with a scan tool, the test should illuminate while commanding the headlamp ON.

• If the test lamp does not illuminate and the circuit fuse is good, test the control circuit for an open/high resistance.

• If the test lamp does not illuminate and the circuit fuse is open, test the control circuit for a short to ground.

5. If all circuits test normal, replace the E4E headlamp-left high beam.

Right High Beam Inoperative
1. Ignition OFF, disconnect the X120 inline harness connector at the E13R headlamp-right.
2. Test for less than 30 ohm between the ground circuit harness connector terminal J and ground.

• If greater than the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal D and ground.
4. Ignition ON, command the High Beam Lamps ON with a scan tool, the test should illuminate while commanding the headlamp ON.

• If the test lamp does not illuminate and the circuit fuse is good, test the control circuit for an open/high resistance.

• If the test lamp does not illuminate and the circuit fuse is open, test the control circuit for a short to ground.

5. If all circuits test normal, replace the E4F headlamp-right high beam.

High Beam Command Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the X50A underhood fuse block.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal listed below and ground.

* Control terminal 13
* Control terminal 14

3. If the test lamp is ON, test the control circuit for a short to voltage.
4. Ignition OFF, connect the X1 harness connector and disconnect the X2 harness connector at the X50A underhood fuse block.
5. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 58 and ground.

• If the test lamp is ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM

6. Connect a test lamp between the control circuit terminal 58 and B+.
7. Ignition ON, command the High Beam Lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.

• 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

8. If all circuits test normal, replace the X50A underhood fuse block.

Component Testing

Relay Test
1. Ignition OFF, disconnect the KR49 headlamp low beam relay.
2. Test for 60-180 ohm between terminals 85 and 86.

• If not within the specified range, replace the KR49 headlamp low beam relay.

3. Test for infinite resistance between the following terminals:

* 30 and 86
* 30 and 87
* 30 and 85
* 85 and 87

• If not the specified value, replace the KR49 headlamp low beam relay.

4. 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 ohm between terminals 30 and 87.

• If greater than the specified range, replace the KR49 headlamp low beam relay.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Fuse Block Replacement (Fuse Block Replacement)
* Headlamp Replacement (Headlamp Replacement)
* Headlamp Ballast Replacement (TT2) (Headlamp Ballast Replacement (TT2))
* Control Module References (Programming and Relearning) for BCM replacement, setup and programming

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