For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics
1 | Did you review the daytime running lamps (DRL) description and operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Lighting Systems
2 |

1. Disengage the parking brake.
2. Place the headlamp switch in the OFF position.
3. Turn ON the ignition, with the engine OFF.

Do the DRLs illuminate?

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

Go to Step 3

3 | Is the park brake indicator illuminated? | Go to Park Brake Indicator Always On in Park Brake | Go to Step 4
4 |

1. Turn OFF the ignition.
2. Disconnect the DRL relay.
3. Probe the DRL diode signal circuit of the DRL relay with a test lamp that is connected to a good ground.
4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Step 8

5 |

1. Turn OFF the ignition.
2. Connect a 40 amp fused jumper wire between the DRL diode signal circuit of the DRL relay and the headlamp low beam supply voltage circuit of the DRL relay.

Do the DRLs illuminate?

Go to Step 6

Go to Step 13

6 |

1. Turn ON the ignition, with the engine OFF.
2. Probe the ignition positive voltage circuit of the DRL relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 14

7 | Connect a test lamp between the ignition positive voltage circuit of the DRL relay and the DRL relay control circuit. Does the test lamp illuminate? | Go to Step 10 | Go to Step 9
8 | Test the DRL diode signal circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 11
9 | Test the DRL relay control circuit for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 12
10 | Inspect for poor connections at the DRL 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 18 | Go to Step 15
11 | Inspect for poor connections at the harness connector of the headlamp 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 18 | Go to Step 16
12 | Inspect for poor connections at the harness connector of the DRL control module. 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 18 | Go to Step 17
13 | Repair an open, high resistance, or short to ground in the headlamp DRL voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 18 | --
14 | Repair an open, high resistance, or short to ground on the DRL relay coil side voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 18 | --
15 | Replace the DRL relay. Did you complete the replacement? | Go to Step 18 | --
16 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | Go to Step 18 | --
17 | Replace the DRL control module. Refer to Daytime Running Lights (DRL) Control Module Replacement . Did you complete the replacement? | Go to Step 18 | --
18 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3