For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Interior Lights Dimming Schematics
1 | Did you review the interior lighting description and operation and perform the necessary inspections? | Go to Step 2 | Go to Symptoms - Lighting Systems
2 |

1. Place the headlamp switch in the PARK position.
2. Operate the Instrument Panel (IP) lamps dimmer switch.

Do the instrument panel lamps operate properly?

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

Go to Step 3

3 |

1. Place the headlamp switch in the OFF position.
2. Disconnect the IP lamps dimmer switch.
3. Probe the headlamp switch park lamps signal circuit of the IP lamps dimmer switch with a test lamp that is connected to a good ground.
4. Place the headlamp switch in the PARK position.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4 |

1. Place the headlamp switch in the OFF position.
2. Connect a 15 amp fused jumper wire between the headlamp switch park lamps signal circuit of the IP lamps dimmer switch and the instrument panel lamps supply voltage circuit of the IP lamps dimmer switch connector.
3. Place the headlamp switch in the PARK position.

Do the instrument panel lamps illuminate?

Go to Step 7

Go to Step 6

5 |

1. Place the headlamp switch in the OFF position.
2. Disconnect the headlamp switch.
3. Probe the battery positive voltage circuit of the headlamp switch with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 9

6 | Test the instrument panel lamp supply voltage 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 13 | Go to Step 10
7 | Inspect for poor connections at the harness connector of the IP lamps dimmer 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 13 | Go to Step 11
8 | 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 13 | Go to Step 12
9 | Repair an open, high resistance, or short to ground on the battery positive voltage circuit of the headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | --
10 | Repair an open or high resistance in the instrument panel lamps ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | --
11 | Replace the I/P lamps dimmer switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | Go to Step 13 | --
12 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the replacement? | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3