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 |
|---|---|---|---|---|
B+, Marker Lamp Relay | 1 | 1 | -- | -- |
Marker Lamp Supply Voltage | 1 | 1 | 2 | -- |
Park Lamps Supply Voltage | 1, 3 | 1, 3 | 4 | -- |
Marker Lamp Relay Control | 2 | 1 | -- | -- |
Ground - Marker Lamp Switch | -- | 1 | -- | -- |
Ground - Marker Lamp | -- | 1 | -- | -- |
1. Marker lamps inoperative 2. Marker lamps always ON 3. Park lamps inoperative 4. Park lamps always ON | ||||
Circuit/System Description
Battery voltage from the MKR LTS Fuse 21 (C4/C5) or Circuit Breaker 21 (C6/C7/C8) located in the I/P-1 fuse block is supplied at all times to the switch side of the MRK LTS Relay. Battery voltage from the RT PARK fuse is applied to the coil side of the relay when the park lamps or headlamps are ON. When the park lamps are ON and the marker lamps switch is in the ON position, ground is applied through the switch contacts and marker lamp relay control circuit energizing the MRK LTS relay. With the relay energized, battery voltage is applied through the switch side of the relay and the marker lamps supply voltage circuits illuminating the marker/clearance lamps. Ground for the marker lamp switch and the clearance lamps is provided at G101. Ground for the outside rearview mirror marker lamps is provided at G102.
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 Verification
Ignition ON, turn the marker lamps ON and OFF, using the marker lamps switch. The marker lamps should turn ON and OFF, when switching between commanded states.
| ⇒ | If all marker lamps are inoperative, refer to Marker Lamps Relay Test. |
| ⇒ | If a single component marker lamp is inoperative, refer to Marker Lamp Circuit Test. |
Circuit/System Testing
Marker Lamps Relay Teat
- Ignition OFF, disconnect the MRK LTS Relay.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal M30 and ground.
- Park lamps ON, verify that a test lamp illuminates between the control circuit terminal M86 and ground.
- Verify that a test lamp does not illuminate between the control circuit terminal M87 and ground.
- Ignition OFF, disconnect marker lamp switch.
- Test for less than 5.0 ohms between ground circuit terminal A and ground.
- Connect a test lamp between the B+ circuit terminal M30 and the control circuit terminal M85.
- Ignition ON, command marker lamps ON and OFF using the marker lamp switch. The test lamp should turn ON and OFF when changing between commanded states.
- If all circuits test normal, test or replace the marker lamp relay.
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the control circuit for an open/high resistance. |
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace marker lamp switch. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, test or replace marker lamp switch. |
Marker Lamp Circuit Test
- Ignition OFF, disconnect the harness connector at the inoperative marker/clearance lamp.
- Verify that a test lamp illuminates between the ground circuit terminal B and B+.
- Connect a test lamp between the appropriate control circuit terminal listed below and ground.
- Command marker lamps ON and OFF using the headlamp switch. Test lamp should turn ON and OFF when changing between commanded states.
- If all circuits test normal, test or replace the bulb or marker/clearance lamp.
| ⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
| • | Clearance and identification lamps terminal A |
| • | Outside rearview mirror terminal G |
| ⇒ | If the lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. |
Component Testing
Marker Lamp Switch
- Ignition OFF, disconnect the marker lamps switch.
- With the switch in the open position, test for infinite resistance between the control terminal C and the ground terminal A.
- With the switch in the closed position, test for less than 2.0 ohm between the control terminal C and the ground terminal A.
| ⇒ | If less than the specified range, replace the marker lamp switch. |
| ⇒ | If greater than the specified range, replace the marker lamp switch. |
Relay
- Ignition OFF, disconnect the MRK LTS relay.
- Test for 70-100 ohms between terminals M85 and M86.
- Test for infinite resistance between the following terminals:
- Test for less than 1.0 ohm between terminals M30 and M87A.
- Install a 10A fused jumper wire between relay terminal M85 and B+. Install a jumper wire between relay terminal M86 and ground. Test for less than 1.0 ohm between terminals M30 and M87.
| ⇒ | If the resistance is not within the specified range, replace the appropriate relay. |
| • | M30 and M86 |
| • | M30 and M87 |
| • | M30 and M85 |
| • | M85 and M87 |
| ⇒ | If not the specified value, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
