For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Interior Lights Dimming Schematics
1 | Did you perform the Lighting System Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Lighting Systems
2 | Is only one component inoperative? | Go to Step 6 | Go to Step 3
3 |

1. Turn on the ignition.
2. Turn the headlamp switch to the PARK position.
3. Do not disconnect the headlamp switch from its connector.
4. Probe the parklamps supply voltage circuit of the interior lamps dimming switch connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 9

4 |

1. Disconnect the headlamp switch connector.
2. Probe the ground supply circuit of the interior lamps dimming switch connector with a test lamp that is connected to B+.

Does the test lamp illuminate?

Go to Step 5

Go to Step 8

5 | Test for an open or high resistance in the interior lamps dimming control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10
6 | Test for an open or high resistance in the interior lamp dimming control circuit of the inoperative component. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 7
7 | Test for an open or high resistance in the ground circuit of the inoperative component. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11
8 | Repair the open or high resistance in the ground circuit of the interior dimming switch . Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 12 | --
9 | Repair the open or high resistance in the parklamp supply voltage circuit of the interior dimming switch . Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 12 | --
10 | Replace the headlamp switch. Refer to Headlamp Switch Replacement . Did you complete the repair? | Go to Step 12 | --
11 | Replace the inoperative component. Did you complete the repair? | Go to Step 12 | --
12 |

1. Connect all connectors and components that were previously disconnected.
2. Verify that the interior lamps dim properly.

Do the interior lamps dim properly?

System OK

Go to Step 2