Pinpoint Test U: One Turn Signal Lamp Is Inoperative/Always On
Turn Signal and Hazard Lamps
Pinpoint Test U: 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 over the High Speed Controller Area Network (HS-CAN) to the Body Control Module (BCM) indicating that the multifunction switch is in the OFF, LH or RH TURN position. When the BCM (Body Control Module) receives a message for a LH or RH turn signal, the BCM (Body Control Module) provides on/off voltage to the appropriate turn lamps.
The front and rear turn lamps share the same fused voltage supply as the rear stoplamps.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Bulb socket
- Exterior mirror
- BCM (Body Control Module)
PINPOINT TEST U : 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.
U1 CHECK THE STOPLAMPS
- Apply and release the brake pedal while observing the stoplamps.
Do the stoplamps operate correctly?
Yes
GO to U2.
No
REFER to Stoplamps Testing and Inspection.
U2 DETERMINE IF A TURN LAMP IS ALWAYS ON
- Ignition ON.
- Observe the front and the rear turn lamps.
Is any turn lamp always on?
Yes
GO to U3.
No
GO to U4.
U3 CHECK THE TURN LAMP OUTPUT CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280F (front turn lamp).
- Disconnect: BCM (Body Control Module) C2280C (rear turn lamp).
- Ignition ON.
Does the turn lamp in question continue to illuminate?
Yes
For the LH front turn lamp, REPAIR circuit CLS21 (BU/GN) for a short to voltage. TEST the system for normal operation.
For the RH front turn lamp, REPAIR circuit CLS25 (YE/VT) for a short to voltage. TEST the system for normal operation.
For the LH rear turn lamp, REPAIR circuit CLS23 (GY/OG) for a short to voltage. TEST the system for normal operation.
For the RH rear turn lamp, REPAIR circuit CLS27 (GN/OG) for a short to voltage. TEST the system for normal operation.
No
GO to U9.
U4 CHECK FOR VOLTAGE TO THE REAR LAMP OR THE FRONT BULB SOCKET
- Ignition OFF.
- Disconnect: Inoperative Turn Lamp.
- Activate the hazard lamp function.
- Measure the voltage between the inoperative turn lamp, harness side and ground as follows:
Inoperative Turn Lamp Connector-Pin Circuit LH front (Edge) C1023-3 CLS21 (BU/GN) RH front (Edge) C1043-3 CLS25 (YE/VT) LH front (MKX) C1115-3 CLS21 (BU/GN) RH front (MKX) C1116-3 CLS25 (YE/VT) LH rear (Edge) C414-3 CLS23 (GY/OG) RH rear (Edge) C417-3 CLS27 (GN/OG)
Does the voltage alternate between 0 and greater than 10 volts?
Yes
GO to U5.
No
GO to U6.
U5 CHECK THE TURN LAMP GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between the inoperative turn lamp or exterior mirror, harness side as follows:
Inoperative Turn Lamp Connector-Pin/ Circuit Connector-Pin/ Circuit LH front (Edge) C1023-3 CLS21 (BU/GN) C1023-1 GD120 (BK/GN) RH front (Edge) C1043-3 CLS25 (YE/VT) C1043-1 GD123 (BK/GY) LH front (MKX) C1115-3 CLS21 (BU/GN) C1115-1 GD120 (BK/GN) RH front (MKX) C1116-3 CLS25 (YE/VT) C1116-1 GD123 (BK/GY) LH rear (Edge) C414-3 CLS23 (GY/OG) C414-1 GD149 (BK/GY) RH rear (Edge) C417-3 CLS27 (GN/OG) C417-1 GD151 (BK/GN)
Does the 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 a rear turn lamp, REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.
No
REPAIR the turn lamp ground circuit in question for an open. TEST the system for normal operation.
U6 CHECK THE BULB SOCKET OR REAR LAMP JUMPER HARNESS FOR A SHORT TO GROUND
- Deactivate the hazard 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 BCM (Body Control Module) on-demand self-test(required to enable the turn lamp output driver if DTC U1000:00 is present).
- Activate the hazard lamp function.
- Measure the voltage between the inoperative turn lamp, harness side and ground as follows:
Inoperative Turn Lamp Connector-Pin Circuit LH front (Edge) C1023-3 CLS21 (BU/GN) RH front (Edge) C1043-3 CLS25 (YE/VT) LH front (MKX) C1115-3 CLS21 (BU/GN) RH front (MKX) C1116-3 CLS25 (YE/VT) LH rear (Edge) C414-3 CLS23 (GY/OG) RH rear (Edge) C417-3 CLS27 (GN/OG)
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 a rear turn lamp, REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.
No
GO to U7.
U7 CHECK THE TURN LAMP OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Deactivate the hazard lamp function.
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280F (front turn lamp).
- Disconnect: BCM (Body Control Module) C2280C (rear turn lamp).
- Measure the resistance between the inoperative turn lamp, harness side and ground as follows:
Inoperative Turn Lamp Connector-Pin Circuit LH front (Edge) C1023-3 CLS21 (BU/GN) RH front (Edge) C1043-3 CLS25 (YE/VT) LH front (MKX) C1115-3 CLS21 (BU/GN) RH front (MKX) C1116-3 CLS25 (YE/VT) LH rear (Edge) C414-3 CLS23 (GY/OG) RH rear (Edge) C417-3 CLS27 (GN/OG)
Is the resistance greater than 10,000 ohms?
Yes
GO to U8.
No
REPAIR the BCM (Body Control Module) turn lamp output 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.
U8 CHECK THE BCM (Body Control Module) TURN LAMP OUTPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the inoperative 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 (Edge) C1023-3C2280F-8 CLS21 (BU/GN) RH front (Edge) C1043-3C2280F-7 CLS25 (YE/VT) LH front (MKX) C1115-3C2280F-8 CLS21 (BU/GN) RH front (MKX) C1116-3C2280F-7 CLS25 (YE/VT) LH rear (Edge) C414-3C2280C-14 CLS23 (GY/OG) RH rear (Edge) C417-3C2280C-15 CLS27 (GN/OG)
Is the resistance less than 5 ohms?
Yes
GO to U9.
No
REPAIR the BCM (Body Control Module) turn lamp output circuit in question for an open. TEST the system for normal operation.
U9 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.