Pinpoint Test M: One Turn Signal Lamp Is Inoperative/Always On
Turn Signal and Hazard Lamps
Pinpoint Test M: One Turn Signal Lamp Is Inoperative/Always On
Normal Operation
The Steering Column Control Module (SCCM) monitors multifunction switch input. The SCCM (Steering Column Control Module) sends a message to the Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN), indicating the multifunction switch is in the OFF, LH or RH TURN position. When the BCM (Body Control Module) receives a message indicating a LH or RH turn request, the BCM (Body Control Module) provides on/off voltage to the appropriate turn lamps.
The front turn lamps share the same fuses as the rear stoplamps. The rear turn lamps are controlled utilizing the rear stoplamp circuitry.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Bulb socket
- Exterior mirror turn lamp
- Exterior mirror
- BCM (Body Control Module)
PINPOINT TEST M : ONE TURN SIGNAL LAMP IS INOPERATIVE/ALWAYS ON
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
M1 CHECK THE STOPLAMPS
- Apply and release the brake pedal while observing the stoplamps.
Do the stoplamps operate correctly?
Yes
GO to M2.
No
GO to Pinpoint Test J Pinpoint Test J: One Or More Stoplamps Are Inoperative.
M2 DETERMINE IF A TURN LAMP IS ALWAYS ON
- Ignition ON.
- Observe the front turn lamps and the signal mirror lamps if equipped.
Is any turn lamp always on?
Yes
GO to M3.
No
GO to M4.
M3 CHECK THE TURN LAMP OUTPUT CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280F.
- Ignition ON.
Does the turn lamp in question continue to illuminate?
Yes
For a LH turn lamp, REPAIR circuit CLS21 (BU/GN) for a short to voltage between the lamp and the BCM (Body Control Module). TEST the system for normal operation.
For a RH turn lamp, REPAIR circuit CLS25 (YE/VT) for a short to voltage between the lamp and the BCM (Body Control Module). TEST the system for normal operation.
No
GO to M10.
M4 CHECK FOR VOLTAGE TO THE INOPERATIVE TURN LAMP
NOTE: If both exterior mirror turn lamps are inoperative, verify the BCM (Body Control Module) fuse 47 (15A) is OK. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short [1][2]Diagrams By Number.
- Ignition OFF.
- Disconnect: Inoperative Turn Lamp.
- Activate the hazard flasher lamp function.
- For a front turn lamp, measure the voltage between the LH front turn lamp C1023-3, circuit CLS21 (BU/GN), harness side and ground; or between the RH front turn lamp C1043-3, circuit CLS25 (YE/VT), harness side and ground.
- For an exterior mirror turn lamp, measure the voltage between the LH exterior mirror C521-10, circuit CLS21 (BU/GN), harness side and ground; or between the RH exterior mirror C615-10, circuit CLS25 (YE/VT), harness side and ground.
Does the voltage alternate between 0 and greater than 10 volts?
Yes
GO to M5.
No
GO to M7.
M5 CHECK THE TURN LAMP GROUND CIRCUIT FOR AN OPEN
- For a front turn lamp, measure the voltage between the LH front turn lamp C1023-3, circuit CLS21 (BU/GN), harness side and the LH front turn lamp C1023-1, circuit GD123 (BK/GY), harness side; or between the RH front turn lamp C1043-3, circuit CLS25 (YE/VT), harness side and the RH front turn lamp C1043-1, circuit GD120 (BK/GN), harness side.
- For an exterior mirror turn lamp, measure the voltage between the LH exterior mirror C521-10, circuit CLS21 (BU/GN), harness side and the LH exterior mirror C521-8, circuit GD134 (BK/VT), harness side; or between the RH exterior mirror C615-10, circuit CLS25 (YE/VT), harness side and the RH exterior mirror C615-8, circuit GD139 (BK/YE), harness side.
Does the voltage alternate between 0 and greater than 10 volts?
Yes
For a front turn lamp, INSTALL a new bulb socket. TEST the system for normal operation.
For exterior mirror turn lamp, GO to M6.
No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.
M6 CHECK THE CIRCUITS TO THE LED ASSEMBLY FOR AN OPEN
- Turn the hazard function off.
- Disconnect: Suspect LED Turn Lamp.
- Measure the resistance between the suspect exterior mirror pin 10, component side and the LED turn lamp connector pin 1 (GN/WH), harness side; and between the suspect exterior mirror pin 8, component side and the LED turn lamp connector pin 2 (BK), harness side.
Are the resistances less than 5 ohms?
Yes
INSTALL a new exterior mirror turn lamp. REFER to Side Lamp Assembly - Outside Rear View Mirror . TEST the system for normal operation.
No
INSTALL a new exterior mirror. TEST the system for normal operation.
M7 REPEAT THE ON-DEMAND SELF-TEST AND CHECK FOR VOLTAGE TO THE INOPERATIVE TURN LAMP
- Deactivate the hazard flasher lamp function.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) Self-Test.
- Clear the DTCs and repeat the self-test (required to enable the turn lamp output driver if DTC U1000:00 is present).
- Activate the hazard flasher lamp function.
- For a front lamp, measure the voltage between the LH front turn lamp C1023-3, circuit CLS21 (BU/GN), harness side and ground; or between the RH front turn lamp C1043-3, circuit CLS25 (YE/VT), harness side and ground.
- For an exterior mirror turn lamp, measure the voltage between the LH exterior mirror C521-10, circuit CLS21 (BU/GN), harness side and ground; or between the RH exterior mirror C615-10, circuit CLS25 (YE/VT), harness side and ground.
Does the voltage alternate between 0 and greater than 10 volts?
Yes
For a front turn lamp, INSTALL a new bulb socket. TEST the system for normal operation.
For an exterior mirror turn lamp, INSTALL a new exterior mirror in question. TEST the system for normal operation.
No
GO to M8.
M8 CHECK THE TURN LAMP OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Turn the hazard lamp function off.
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280F.
- For a front turn lamp, measure the resistance between the LH front turn lamp C1023-3, circuit CLS21 (BU/GN), harness side and ground; or between the RH front turn lamp C1043-3, circuit CLS25 (YE/VT), harness side and ground.
- For an exterior mirror turn lamp, measure the resistance between the LH exterior mirror C521-10, circuit CLS21 (BU/GN), harness side and ground; or between the RH exterior mirror C615-10, circuit CLS25 (YE/VT), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to M9.
No
REPAIR the circuit in question for a short to ground. After the repair:
If no DTCs are present, TEST the system for normal operation.
If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the turn lamp output driver if DTC U1000:00 is present). TEST the system for normal operation.
If DTC U3000:49 is present, INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
M9 CHECK THE BCM (Body Control Module) TURN LAMP OUTPUT CIRCUIT FOR AN OPEN
- For a front turn lamp, measure the resistance between the inoperative front turn lamp, harness side and the BCM (Body Control Module), harness side as follows:
Inoperative Turn Lamp Connector-Pin BCM (Body Control Module) Connector-Pin Circuit LH front C1023-3C2280F-8 CLS21 (BU/GN) RH front C1043-3C2280F-7 CLS25 (YE/VT)
- For an exterior mirror turn lamp, measure the resistance between the exterior mirror in question, harness side and the BCM (Body Control Module), harness side as follows:
Exterior Mirror Connector-Pin BCM (Body Control Module) Connector-Pin Circuit LH exterior mirror C521-10C2280F-9 CLS21 (BU/GN) RH exterior mirror C615-10C2280F-10 CLS25 (YE/VT)
Is the resistance less than 5 ohms?
Yes
GO to M10.
No
REPAIR the circuit in question for an open. TEST the system for normal operation.
M10 CHECK FOR CORRECT BCM (Body Control Module) OPERATION
- Disconnect all the BCM (Body Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM (Body Control Module) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.