For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Observe the courtesy lamps.
2. Open and close all of the vehicle doors.
3. Place the courtesy lamp switch in the ON position.

Do the courtesy lamps illuminate as expected?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3 | Is only one courtesy lamp inoperative? | Go to Step 4 | Go to Step 5
4 | Test the voltage supply and ground circuits of the inoperative courtesy lamp for an open or high resistance. Did you find and correct the condition? | Go to Step 23 | Go to Step 19
5 | Are all courtesy lamps inoperative at all times? | Go to Step 6 | Go to Step 7
6 | Test the courtesy lamp supply voltage and battery positive voltage circuits of the body control module (BCM) for an open, high resistance, or short to ground. Did you find and correct the condition? | Go to Step 23 | Go to Step 17
7 | Are the courtesy lamps inoperative from the front dome lamp switch only? | Go to Step 8 | Go to Step 9
8 | Test the ground circuit of the front dome lamp switch for an open or high resistance. Did you find and correct the condition? | Go to Step 23 | Go to Step 16
9 | Are the courtesy lamps inoperative from all doors and the liftgate? | Go to Step 10 | Go to Step 12
10 |

1. Open the doors.
2. Connect a test lamp between the courtesy lamp low control circuit of the front dome lamp connector and battery positive voltage.

Does the test lamp illuminate?

Go to Step 16

Go to Step 11

11 | Test the low control circuit of the BCM for an open or high resistance. Did you find and correct the condition? | Go to Step 23 | Go to Step 17
12 | With the scan tool, observe the parameter of the door that does not illuminate the courtesy lamps using the following:

• | DRIVER DOOR SWITCH

• | PASS DOOR SWITCH

• | LIFTGATE AJAR SWITCH

Does the parameter switch from HIGH to LOW as expected?

Go to Step 17

Go to Step 13

13 |

1. Close all doors that illuminate the courtesy lamps.
2. Disconnect the inoperative door ajar switch connector.
3. Connect a 3-amp fused jumper wire between the signal circuit of the connector and a good ground.

Do the courtesy lamps illuminate?

Go to Step 15

Go to Step 14

14 | Test the signal circuit of the switch for an open or high resistance. Did you find and correct the condition? | Go to Step 23 | Go to Step 17
15 | Test the ground circuit of the switch for an open or high resistance. Did you find and correct the condition? | Go to S Step 23 | Go to Step 18
16 | Inspect for poor connections at the harness connector of the front courtesy lamp assembly. Did you find and correct the condition? | Go to Step 23 | Go to Step 20
17 | Inspect for poor connections at the harness connector of the BCM. Did you find and correct the condition? | Go to Step 23 | Go to Step 21
18 | Inspect for poor connections at the harness connector of the inoperative switch. Did you find and correct the condition? | Go to Step 23 | Go to Step 22
19 | Replace the bulb. Did you complete the replacement? | Go to Step 23 | --
20 | Replace the bulb or lamp assembly. Did you complete the replacement? | Go to Step 23 | --
21 | Replace the BCM. Refer to Body Control Module Replacement . Did you complete the replacement? | Go to Step 23 | --
22 | Replace the inoperative switch. Did you complete the replacement? | Go to Step 23 | --
23 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3