For 1990-2009 cars

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Inspect the headlamps. Do the headlamps work? | -- | Go to Step 3 | Go to Step 2
2 | Repair the headlamps. Are the rear combination lamps still inoperative? | -- | Go to Step 3 | System OK
3 |

1. Turn the tail lamps and side turn signal lamps ON.
2. Use a voltmeter to measure voltage at the bulb socket positive terminal.

Does voltage at the bulb socket measure within the specified range?

11-14 V

Go to Step 4

Go to Step 7

4 | Connect an ohmmeter between ground and the lamp socket negative terminal. Is the resistance equal to the specified value? | 0 ohms | Go to Step 6 | Go to Step 5
5 | Repair the ground circuit for the lamps. Is the repair complete? | -- | System OK | --
6 | Replace the faulty bulbs. Is the repair complete? | -- | System OK | --
7 | Inspect fuses EF20 and EF21. Are any of the fuses open? | -- | Go to Step 8 | Go to Step 9
8 |

1. Inspect for a short circuit and repair it, if necessary.
2. Replace the fuse.

Is the repair complete?

--

System OK

--

9 |

1. Turn the headlamps ON.
2. Measure the voltage at intelligent switching unit (ISU) connector terminal C8 for the left side tail lamp and side marker lamp, and ISU connector terminal C4 for the right side tail lamp and side marker lamp.

Does the voltage at the connector measure within the specified range?

11-14 V

Go to Step 11

Go to Step 10

10 |

1. Inspect the ISU.
2. Replace the ISU.

Is the repair complete?

--

System OK

--

11 | Repair the open circuit between the fused EF20 and EF21 and the tail lamps and/or side turn signal lamps. Is the repair complete? | -- | System OK | --