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For 1990-2009 cars only

Headlamps Inoperative - High Beams V6

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the headlamps.
  2. Ensure that the headlamp dimmer switch is in the HIGH position.

Do the high beams illuminate?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Is only one high beam headlamp inoperative?

Go to Step 14

Go to Step 4

4

Place the headlamp dimmer switch in to the flash to pass (FTP) position.

Do the high beam headlamps illuminate?

Go to Step 7

Go to Step 5

5

  1. Disconnect the body control module (BCM) connector C1.
  2. Connect a jumper between the headlamp high beam relay control circuit and ground.

Do the high beam headlamps illuminate?

Go to Step 9

Go to Step 6

6

  1. Remove the high beam relay.
  2. Install a fused jumper between the battery positive voltage supply circuit and the switched high beam voltage supply circuit.

Do the high beam headlamps illuminate?

Go to Step 10

Go to Step 13

7

  1. Reinstall the high beam relay.
  2. Disconnect the multifunction switch.
  3. Connect a jumper between the headlamp dimmer switch high beam signal circuit and ground.

Do the high beam headlamps illuminate?

Go to Step 11

Go to Step 8

8

Test for poor connection, short to battery positive voltage or an open in the headlamp dimmer switch high beam signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 19

9

  1. Reconnect the BCM connector C1.
  2. Disconnect the multifunction switch.
  3. Connect a jumper between the headlamp dimmer switch high beam signal circuit and ground.

Do the headlamps illuminate?

Go to Step 11

Go to Step 19

10

Test for a short to battery positive voltage, a poor connection or an open in the headlamp high beam relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 12

11

Inspect for a poor connection at the harness connector of the multifunction turn signal switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 15

12

Inspect for a poor connection at the harness connector of the high beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 16

13

Inspect for a poor connection at the harness connectors of the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 17

14

Inspect the inoperative high beam headlamp voltage supply and ground circuit for a high resistance, short to ground, short to battery positive voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 20

Go to Step 18

15

Replace the multifunction turn signal switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 20

Go to Step 3

16

Replace the high beam relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 20

--

17

Replace the underhood fuse block. Refer to Relay Replacement in Wiring Systems.

Did you complete the repair?

Go to Step 20

--

18

Replace the inoperative high beam headlamp. Refer to Headlamp Assembly or Headlamp Bulb Replacement .

Did you complete the replacement?

Go to Step 20

--

19

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 20

--

20

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Headlamps Inoperative - High Beams V8 High Beam PCB Relay

Diagnostic Instructions

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

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

High Beam Headlamp Relay Control Circuit

2

1

B2580

--

  1. Headlamps Inoperative - High Beams
  2. Headlamps Always On - Low or High

Circuit/System Description

Voltage is applied at all times to the high beam headlamp relay from battery voltage. When the dimmer switch or the flash to pass switch send a ground input to the BCM, the BCM sends a ground output to the high beam relay. The high beam relay is activated then the switch side of the relay closes and turns on the lights.

Reference Information

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference

Lighting Systems Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

  1. Ignition ON, turn the park lamps and head lamps ON. Switch the head lamps from low to high beam. The low beam and high beam lamps should illuminate.
  2. Observe the scan tool high beam lamps switch parameter while switching the head lamps from low to high beam. The reading should change between ON and OFF.
  3. If the high beam lamps do not illuminate and the high beam lamp switch parameter does not change while switching the head lamps from low to high beam--Test input side of BCM for inoperative condition in Circuit/System Testing.
    If the high beam lamps do not illuminate and the high beam lamp switch parameter does change between ON and OFF while switching the head lamps from low to high beam--Test output side of BCM for inoperative condition in Circuit/System Testing.

Circuit/System Testing

Test Input Side of BCM For Inoperative High Beam Lamps

  1. Ignition OFF, disconnect the malfunction turn signal lever harness connector at the switch.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal D and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool high beam lamp switch parameter displays OFF.
  5. If not the specified value, test the signal circuit terminal E for a short to ground. If the circuit tests normal, replace the body control module.
  6. Install a 3A fused jumper wire between the signal circuit terminal E and the ground circuit terminal D. Verify the scan tool high beam switch parameter displays closed.
  7. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the body control module.
  8. If all circuits test normal, test or replace the multifunction turn signal lever.

Test Output Side of BCM For Inoperative High Beam Lamps

  1. Disconnect the harness connector at both high beam lamps.
  2. Test for less than 1.0 ohm of resistance between the appropriate high beam lamp ground circuit terminal B and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Connect a test lamp between the control circuit terminal A and ground.
  5. 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.
  6. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BEC.
    If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the BEC.
    If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, replace the appropriate high beam lamp bulb socket.
  7. If all circuits test normal, replace the appropriate high beam lamp bulb socket.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Accessory Wiring Junction Block Replacement
    •  Headlamp Assembly or Headlamp Bulb Replacement
    •  Control Module References for BCM replacement, setup, and programming