For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics Connector End View Reference: Lighting Systems Connector End Views , Data Communication Connector End Views , or Wiper/Washer Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 | Verify that the low beam headlamps are inoperative. Do the low beam headlamps operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3
3 | Is only one low beam headlamp inoperative? | Go to Step 4 | Go to Step 5
4 |

1. Inspect the inoperative bulb for an open filament and connector for poor terminal contact and replace/repair, as necessary. Refer to Headlamp Bulb Replacement or Wiring Repairs .
2. If the condition above does not exist, repair the open, high resistance or short to ground in the low beam headlamp supply voltage circuit or ground circuit to the inoperative lamp. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 18

--

5 | Does the wiper activated headlamp (WAH) function of the wiper system operate normally? | Go to Step 8 | Go to Step 6
6 |

1. Block the wheels.
2. Place the ignition switch in the RUN position with the engine OFF.
3. Place the gearshift lever in DRIVE.
4. Place the wiper switch in the LO speed position.
5. Use the scan tool to monitor the Front Wipers Active input to the BCM.

Does the scan tool display Active after approximately 3 cycles of the wiper blades?

Go to Step 13

Go to Step 7

7 | Test the windshield wiper switch signal 1 circuit for an open, high resistance, or short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition? | Go to Step 18 | Go to Step 12
8 | Disconnect the turn signal/multifunction switch. Do the low beam headlamps illuminate? | Go to Step 11 | Go to Step 9
9 |

1. Remove the beam select relay. Refer to Relay Replacement .
2. Test for a voltage signal at the headlamp high beam relay control circuit terminal in the underhood fuse block. Refer to Electrical Center Identification Views and Circuit Testing .

Was a voltage signal present?

Go to Step 10

Go to Step 14

10 | Test for a short to voltage in the headlamp high beam relay control circuit. Refer to Electrical Center Identification Views and Circuit Testing . Did you find and correct a condition? | Go to Step 18 | Go to Step 13
11 | Test for a short to ground in the headlamp dimmer switch high beam signal circuit or flash to pass switch signal circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition? | Go to Step 18 | Go to Step 12
12 | Inspect for poor connections at the harness connector of the turn signal/multifunction switch. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 18 | Go to Step 15
13 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 18 | Go to Step 16
14 | Inspect for poor connections at the harness connector of the underhood fuse block and beam select relay. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 18 | Go to Step 17
15 | Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the repair? | Go to Step 18 | --
16 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 18 | --
17 | Replace the beam select relay. Refer to Relay Replacement . Did you complete the repair? | Go to Step 18 | --
18 |

1. Use the scan tool in order to clear any induced DTCs.
2. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3