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 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 position, the BCM (Body Control Module) provides on/off voltage to the appropriate turn lamps.
The front and exterior mirror turn lamps share the same voltage supply as the rear stoplamps. The rear turn lamps are controlled utilizing the rear stoplamp circuitry.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Bulb holder
- 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 (Front Turn Lamp).
- Disconnect: BCM (Body Control Module) C2280C (Exterior Mirror 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 exterior mirror turn lamp, REPAIR circuit CLS23 (GY/OG) for a short to voltage. TEST the system for normal operation.
For the RH exterior mirror turn lamp, REPAIR circuit CLS27 (GN/OG) for a short to voltage. TEST the system for normal operation.
No
GO to M9.
M4 CHECK FOR VOLTAGE TO THE EXTERIOR MIRROR OR THE BULB HOLDER
- Ignition OFF.
- Disconnect: Inoperative Front Turn Lamp or Exterior Mirror.
- Turn the hazard lamp function on.
- Measure the voltage between the inoperative front turn lamp or exterior mirror, harness side and ground as follows:
Inoperative Turn Lamp/Exterior Mirror Connector-Pin Circuit LH front C1023-3 CLS21 (BU/GN) RH front C1043-3 CLS25 (YE/VT) LH exterior mirror C521-8 CLS23 (GY/OG) RH exterior mirror C601-8 CLS27 (GN/OG)
Does the voltage fluctuate between 0 and greater than 10 volts?
Yes
GO to M5.
No
GO to M6.
M5 CHECK THE EXTERIOR MIRROR OR THE BULB HOLDER GROUND CIRCUIT FOR AN OPEN
- Measure the voltage between the inoperative turn lamp or exterior mirror, harness side as follows:
Inoperative Turn Lamp/Exterior Mirror Connector-Pin/ Circuit Connector-Pin/ Circuit LH front C1023-3 CLS21 (BU/GN) C1023-1 GD122 (BK) RH front C1043-3 CLS25 (YE/VT) C1043-1 GD124 (BK/VT) LH exterior mirror C521-8 CLS23 (GY/OG) C521-7 GD137 (BK/WH) RH exterior mirror C601-8 CLS27 (GN/OG) C601-7 GD179 (BK/VT)
Does the voltage fluctuate between 0 and greater than 10 volts?
Yes
For a front turn lamp, INSTALL a new bulb holder. TEST the system for normal operation.
For an exterior mirror turn lamp, INSTALL a new exterior mirror. TEST the system for normal operation.
No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.
M6 CHECK THE EXTERIOR MIRROR OR THE BULB HOLDER FOR A SHORT TO GROUND
- Turn the hazard lamp function off.
- 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).
- Turn the hazard lamp function on.
- Measure the voltage between the inoperative turn lamp or exterior mirror, harness side and ground as follows:
Inoperative Turn Lamp/Exterior Mirror Connector-Pin Circuit LH front C1023-3 CLS21 (BU/GN) RH front C1043-3 CLS25 (YE/VT) LH exterior mirror C521-8 CLS23 (GY/OG) RH exterior mirror C601-8 CLS27 (GN/OG)
Does the voltage fluctuate between 0 and greater than 10 volts?
Yes
For a front turn lamp, INSTALL a new bulb holder. TEST the system for normal operation.
For an exterior mirror turn lamp, INSTALL a new exterior mirror. TEST the system for normal operation.
No
GO to M7.
M7 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 (Front Turn Lamp).
- Disconnect: BCM (Body Control Module) C2280C (Exterior Mirror Turn Lamp).
- Measure the resistance between the inoperative turn lamp or exterior mirror, harness side and ground as follows:
Inoperative Turn Lamp/Exterior Mirror Connector-Pin Circuit LH front C1023-3 CLS21 (BU/GN) RH front C1043-3 CLS25 (YE/VT) LH exterior mirror C521-8 CLS23 (GY/OG) RH exterior mirror C601-8 CLS27 (GN/OG)
Is the resistance greater than 10,000 ohms?
Yes
GO to M8.
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.
M8 CHECK THE BCM (Body Control Module) TURN LAMP OUTPUT CIRCUIT FOR AN OPEN
- Measure the resistance between the inoperative turn lamp or exterior mirror, harness side and the BCM (Body Control Module), harness side as follows:
Inoperative Turn Lamp/Exterior Mirror 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) LH exterior mirror C521-8C2280C-14 CLS23 (GY/OG) RH exterior mirror C601-8C2280C-15 CLS27 (GN/OG)
Is the resistance less than 5 ohms?
Yes
GO to M9.
No
REPAIR the circuit in question for an open. TEST the system for normal operation.
M9 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.