For 1990-2009 cars

## Daytime Running Lamps (DRL) Headlamps Inoperative Buick

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Headlights System Check? | -- | Go to Step 2 | Go to Headlight System Check
2 |

1. Disconnect the Lamp Control Module (LCM) connector C2.
2. Cover the ambient light sensor.
3. Connect a DMM from the LCM connector C2 cavity A5 (WHT) to ground.

Is the resistance greater than the specified value?

31K ohms

Go to Step 3

Go to Step 11

3 |

1. Expose the ambient light sensor to a bright incandescent light.
2. Connect a DMM from the LCM connector C2 cavity A5 (WHT) to ground.

Is the resistance less than the specified value?

23K ohms

Go to Step 4

Go to Step 11

4 |

1. Connect a DMM from the LCM connector C2 cavity A7 (PNK) to ground.
2. Turn the ignition switch to the RUN position.

Is the voltage within the specified range?

10-15 V

Go to Step 5

Go to Step 14

5 |

1. Connect a DMM from the LCM connector C2 cavity A8 (LT GRN) and ground.
2. Place the gear selector in DRIVE.

Is the voltage within the specified range?

10-15 V

Go to Step 15

Go to Step 6

6 |

1. Disconnect the LCM connector C1.
2. Connect a fused jumper from the LCM connector C1 cavity G (RED) to cavity D (GRY).

Do the high beam headlamps light at a reduced intensity?

--

Go to Step 10

Go to Step 7

7 | Inspect for an open or short to ground in CKT 589 (GRY) between the LCM and the left high beam headlamp. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems. Is CKT 589 OK? | -- | Go to Step 8 | Go to Step 18
8 | Inspect for an open in CKT 11 (LT GRN) between the left high beam headlamp and the right high beam headlamp. Refer to Testing for Continuity in Wiring Systems. Is CKT 11 OK? | -- | Go to Step 9 | Go to Step 18
9 | Repair the open in CKT 1150 (BLK) between the right high beam headlamp and S151. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --
10 | Replace the LCM. Is the repair complete? | -- | Go to Headlight System Check | --
11 | Inspect for an open or short to ground in CKT 278 (WHT) between the LCM and the ambient light sensor. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems. Is CKT 278 OK? | -- | Go to Step 12 | Go to Step 18
12 | Inspect for an open in CKT 251 (BLK/WHT) between the ambient light sensor and S249. Refer to Testing for Continuity in Wiring Systems. Is CKT 251 OK? | -- | Go to Step 13 | Go to Step 18
13 | Replace the ambient light sensor. Refer to Sunload and Twilight Sentinel Sensor Replacement and Defroster Grille Replacement in Instrument Panel, Gauges and Console. Is the repair complete? | -- | Go to Headlight System Check | --
14 | Repair the open in CKT 39 (PNK) between S208 and the LCM. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --
15 | Disconnect the park/neutral position (PNP) switch. Do the daytime running lamps (DRL) light? | -- | Go to Step 17 | Go to Step 16
16 | Repair the short to battery positive voltage (B+) in CKT 275 (LT GRN). Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --
17 | Replace the park/neutral position (PNP) switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle-4T65-E. Is the repair complete? | -- | Go to Headlight System Check | --
18 | Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --

## Daytime Running Lamps (DRL) Headlamps Inoperative Oldsmobile/Pontiac

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Headlights System Check? | -- | Go to Step 2 | Go to Headlight System Check
2 |

1. Disconnect the Lamp Control Module (LCM) connector C2.
2. Cover the ambient light sensor.
3. Connect a DMM from the LCM connector C2 cavity A2 (WHT) to ground.

Is the resistance greater than the specified value?

31K ohms

Go to Step 3

Go to Step 11

3 |

1. Expose the ambient light sensor to a bright incandescent light.
2. Connect a DMM from the LCM connector C2 cavity A2 (WHT) to ground.

Is the resistance less than the specified value?

23K ohms

Go to Step 4

Go to Step 11

4 |

1. Disconnect the LCM connector C1.
2. Connect a DMM from the LCM connector C1 cavity C (PNK) to ground.
3. Turn the ignition switch to the RUN position.

Is the voltage within the specified range?

10-15 V

Go to Step 5

Go to Step 14

5 |

1. Connect a DMM from the LCM connector C2 cavity A7 (LT GRN) to ground.
2. Place the park/neutral position (PNP) switch in DRIVE.

Is the voltage within the specified range?

10-15 V

Go to Step 15

Go to Step 6

6 | Connect a fused jumper from the LCM connector C1 cavity E (RED) to cavity G (GRY). Do the low beam headlamps light at a reduced intensity? | -- | Go to Step 10 | Go to Step 7
7 | Inspect for an open or short to ground in CKT 589 (GRY) between the LCM and the daytime running lights (DRL) resistor. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems. Is CKT 589 OK? | -- | Go to Step 8 | Go to Step 18
8 | Inspect for an open in CKT 12 (TAN) between the DRL resistor and S257. Refer to Testing for Continuity in Wiring Systems. Is CKT 12 OK? | -- | Go to Step 9 | Go to Step 18
9 | Replace the DRL resistor. Refer to Daytime Running Lamps (DRL) Resistor Replacement . Is the repair complete? | -- | Go to Headlight System Check | --
10 | Replace the LCM. Is the repair complete? | -- | Go to Headlight System Check | --
11 | Inspect for an open or short to ground in CKT 278 (WHT) between the LCM and the ambient light sensor. Refer to Testing for Continuity or Testing for Short to Ground in Wiring Systems. Is CKT 278 OK? | -- | Go to Step 12 | Go to Step 18
12 | Inspect for an open in CKT 251 (BLK/WHT) wiring between the ambient light sensor and S249. Refer to Testing for Continuity in Wiring Systems. Is CKT 251 OK? | -- | Go to Step 13 | Go to Step 18
13 | Replace the ambient light sensor. Refer to Sunload and Twilight Sentinel Sensor Replacement Defroster Grille Replacement in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --
14 | Repair the open in CKT 3 (PNK) between S205 and the LCM. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --
15 | Disconnect the park/neutral position (PNP) switch. Do the daytime running lamps (DRL) light? | -- | Go to Step 17 | Go to Step 16
16 | Repair the short to battery positive voltage (B+) in CKT 275 (LT GRN) between S296 and the LCM. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --
17 | Replace the park/neutral position (PNP) switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle-4T65-E. Is the repair complete? | -- | Go to Headlight System Check | --
18 | Repair the suspect wiring. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Headlight System Check | --