For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Headlights Schematics and Wiper/Washer Schematics Connector End View Reference: Master Electrical Component List
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install the scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Turn the headlamp switch to the OFF position.
4. With a scan tool, observe the Headlamp Switch parameter in the instrument panel module (IPM) inputs data list.

Does the scan tool indicate the Headlamp Switch parameter is OFF?

Go to Step 3

Go to Step 12

3 | With a scan tool, observe both the Low Beam Relay and High Beam Relay parameters in the instrument panel module (IPM) inputs data list. Does the scan tool indicate the Low Beam and High Beam Relay output parameters are OFF? | Go to Step 7 | Go to Step 4
4 | With a scan tool, observe the Lights On with Wipers parameter in the instrument panel module (IPM) inputs data list. Does the scan tool indicate OFF? | Go to Step 5 | Go to Step 13
5 | With a scan tool, observe the Flash to Pass Switch parameter in the instrument panel module (IPM) inputs data list. Does the scan tool indicate that the Flash to Pass Switch parameter is INACTIVE? | Go to Step 6 | Go to Step 14
6 | With a scan tool, observe the Twilight Enable parameter in the instrument panel module (IPM) exterior lamps data list. Does the scan tool indicate that the Twilight Enable is DISABLED? | Go to Step 22 | Go to Twilight Sentinel Inoperative
7 | Are the high beam headlamps ON? | Go to Step 10 | Go to Step 8
8 |

1. Turn OFF the ignition.
2. Disconnect the headlamp low beam relay.
3. Turn ON the ignition, with the engine OFF.

Do the low beam headlamps turn OFF?

Go to Step 9

Go to Step 23

9 |

1. Turn OFF the ignition.
2. Turn OFF the headlamp switch.
3. Connect a test lamp between the headlamp low beam relay coil side supply voltage circuit and the headlamp low beam relay control circuit.
4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 15

Go to Step 19

10 |

1. Turn OFF the ignition.
2. Disconnect the headlamp high beam relay.
3. Turn ON the ignition, with the engine OFF.

Do the high beam headlamps turn OFF?

Go to Step 11

Go to Step 24

11 |

1. Turn OFF the ignition.
2. Turn OFF the headlamp switch.
3. Connect a test lamp between the headlamp high beam relay coil side supply voltage circuit and the headlamp high beam relay control circuit.
4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 16

Go to Step 20

12 |

1. Turn OFF the ignition.
2. Disconnect the turn signal/multifunction switch.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the Head Lamp Switch parameter in the instrument panel module (IPM) inputs data list.

Does the scan tool indicate that the Head Lamp Switch parameter is OFF?

Go to Step 21

Go to Step 17

13 | Test the windshield wiper switch ON signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 22
14 |

1. Turn OFF the ignition.
2. Disconnect the turn signal/multifunction switch.
3. With a scan tool, observe the Flash to Pass Switch parameter in the instrument panel module (IPM) inputs data list.

Does the scan tool indicate that the Flash to Pass Switch is INACTIVE?

Go to Step 21

Go to Step 18

15 | Locate and repair a short to ground in the headlamp low beam relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 22
16 | Locate and repair a short to ground in the headlamp high beam relay control circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 22
17 | Locate and repair a short to ground in the headlamp switch headlamp ON signal circuit. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 22
18 | Test the flash to pass switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 22
19 | Inspect for poor connections at the low beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 25
20 | Inspect for poor connections at the high beam relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 26
21 | Inspect for poor connections at the harness connector of the turn signal/multifunction switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 27
22 | Inspect for poor connections at the harness connector of the IPM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 29 | Go to Step 28
23 | Locate and repair a short to voltage in the headlamp low beam supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 29 | --
24 | Locate and repair a short to voltage in the headlamp high beam supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 29 | --
25 | Replace the headlamp low beam relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 29 | --
26 | Replace the headlamp high beam relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 29 | --
27 | Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the replacement? | Go to Step 29 | --
28 | Replace the IPM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 29 | --
29 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2