Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Park Lamp Relay B+ | 1 | 1 | -- | -- |
Park Lamp Switch Signal | 2 | 2 | 2 | -- |
Park Lamp Switch Signal | 2 | 2 | 2 | -- |
Park Lamp Relay Control | 1 | 1 | 1 | -- |
Park Lamp Control | 1 | 1 | 1 | -- |
Headlamp Switch Low Reference | -- | 2 | -- | -- |
License Lamp Ground | -- | 1 | -- | -- |
Marker Lamp Ground-- LF | -- | 1 | -- | -- |
Marker Lamp Ground-- RF | -- | 1 | -- | -- |
Park/Turn Signal Lamp Ground -- RF | -- | 1 | -- | -- |
Park/Turn Signal Lamp Ground -- LF | -- | 1 | -- | -- |
Roof Marker Lamps Ground | -- | 1 | -- | -- |
Tail/Stop and Turn Signal Ground -- LF | -- | 1 | -- | -- |
Tail/Stop and Turn Signal Ground -- RF | -- | 1 | -- | -- |
1. Park Lamp Malfunction 2. Park Lamp Switch Malfunction | ||||
Circuit/System Description
The roof marker lamps are a dealer installed option and operate whenever the park lamps are on. When the park lamps or headlamps are turned to the ON position at the headlight switch, voltage is supplied to the roof marker lamps through the park lamp control circuit. The roof marker lamps are grounded at all times at G105.
Diagnostic Aids
Verify that the park lamps are operating correctly prior to diagnosing a roof marker lamp condition.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verfication
- Ignition ON, observe the scan tool Park Lamp Signal parameter while turning the park lamps ON and OFF. The reading should change between Inactive and Active.
- Ignition ON, command the park lamps ON and OFF with a scan tool. The roof marker lamps should turn On and Off.
| ⇒ | If not the specified value, refer to the Park Lamp Switch Circuit Test. |
| ⇒ | If the roof marker lamps do not turn On and Off, refer to the Roof Marker Lamp Malfunction Test. |
Circuit/System Testing
Park Lamp Switch Malfunction
- Ignition OFF, disconnect the harness connector at the headlamp switch.
- Ignition ON, verify the scan tool Park Lamp Signal parameter is Off.
- Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Park Lamp Signal parameter is Active.
- If all circuits test normal, test or replace the headlamp switch.
| ⇒ | If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM. |
Roof Marker Lamp Malfunction
- Ignition OFF, diconnect the harness connector at the inoperative roof marker lamp.
- Exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground..
- Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
- Ignition ON, command the park lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, replace the inoperative roof marker lamp.
| ⇒ | If greater than the specified range, test the ground circuit for and open/high resistance. |
| ⇒ | If the test lamp is always on, test the control circuit for a short to voltage. |
| ⇒ | If the test lamp is always off, test the control circuit for a short to ground or an open/high resistance. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, programming, and setup |
