Pinpoint Test AF: The Turn Signal Lamps Flash Fast And All Bulbs Operate

Turn Signal, Cornering and Hazard Lamps

Pinpoint Tests

Pinpoint Test AF: The Turn Signal Lamps Flash Fast And All Bulbs Operate

Normal Operation

When the multifunction switch is placed in the LH or RH turn position and all 3 bulbs are OK, the Lighting Control Module (LCM) flashes the turn lamps approximately 80 times per minute. The electronics within the LCM can determine when a bulb is inoperative based on the total resistance (or load) of 3 bulbs specified for the vehicle. When one of the 3 bulbs becomes inoperative, the resistance increases and the load decreases. If high resistance is present within turn the signal circuitry, such as corrosion at a ground contact point or a loosely connected pin within a connector, the LCM may interpret this as a bulb out and flash the turn signals fast even though all the bulbs illuminate.

For vehicles with the police option, the rear stop/turn lamp circuits also provide voltage to the coil side of a corresponding emergency flasher relay for the package tray lamps. These relays have no affect on the turn signal operation provided by the LCM.

Possible Causes
- Bulb(s)
- High circuit resistance
- Multifunction switch
- LCM

PINPOINT TEST AF: THE TURN SIGNAL LAMPS FLASH FAST AND ALL BULBS OPERATE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: It is necessary to create a 6-inch jumper wire to carry out the voltage drop testing. Use only 18 gauge wire with one end of the jumper wire having approximately one-half inch of insulation stripped off and the other end having a terminal to accommodate the digital multimeter. The bare wire fits between the bulb and the terminal of the lamp socket.

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AF1 CHECK THE BULBS

- Ignition OFF.
- Inspect the bulbs and make sure they are the correct type.

- Are the correct bulbs installed?

Yes
If both sides flash fast, GO to AF2. If one side flashes fast, GO to AF4.

No
INSTALL the correct bulbs. TEST the system for normal operation.

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AF2 CHECK THE MULTIFUNCTION SWITCH PIN CONNECTION

- Disconnect: Multifunction Switch C202a .
- Inspect the multifunction switch C202a-1, circuit 44 (LB) to make sure the terminal is secure in the connector and that the terminal is not spread open to cause a loose connection with the multifunction switch.
- Is the multifunction switch connection OK?

Yes
GO to AF3.

No
REPAIR the connection to C202a of the multifunction switch. TEST the system for normal operation.

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AF3 CHECK THE CONNECTION AT G410

NOTE: A wire routed directly from the battery ground cable to G410 can be used to bypass the body connection to determine if high resistance is present between the G410 connection and ground.

- Inspect the ground connection G410 and make sure the wires to the eyelet are secure and the connection to the body is clean and free of corrosion.
- Is the connection to the body clean, secure and free of corrosion?

Yes
INSTALL a new multifunction switch. REFER to Steering Column Switches Steering Column Multifunction Switch. TEST the system for normal operation. If the concern is still present, GO to AF9.

No
REPAIR the G410 connection as necessary. TEST the system for normal operation.

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AF4 CHECK THE BULB CONNECTIONS

NOTE: If water intrusion is present within the lamp assembly, the lamp assembly should be repaired or replaced to prevent future electrical concerns.

- Disconnect: Suspect Turn Lamps .
- Inspect all the bulb holders on the suspect side and make sure the terminals are secure in the connector, free of corrosion and that the terminals are not spread open to cause a loose connection with the bulb.
- Is the connection of the bulb clean, secure and free of corrosion?

Yes
GO to AF5.

No
REPAIR the bulb connection as necessary. TEST the system for normal operation.

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AF5 CHECK THE CONNECTIONS AT G102 (LH FRONT), G109 (RH FRONT) AND G410 (REAR)

NOTE: A wire routed directly from the battery ground cable to the ground eyelet can be used to bypass the body connection to determine if high resistance is present between the eyelet connection and ground.

- Inspect the ground connections at G102 (LH front), G109 (RH front) and G410 (rear) and make sure the wires to the eyelets are secure and the connections to the body are clean and free of corrosion.
- Are the connections to the body clean, secure and free of corrosion?

Yes
GO to AF6.

No
REPAIR the G410 connection as necessary. TEST the system for normal operation.

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AF6 CHECK THE PIN CONNECTIONS AT THE MULTIFUNCTION SWITCH CONNECTORS

- Disconnect: Multifunction Switch C202a and C202c .
- Inspect the multifunction switch connector to make sure the terminals are secure in the connector and that the terminals are not spread open to cause a loose connection with the multifunction switch. Refer to the following table for the pin connections.

- Is the multifunction switch connection OK?

Yes
GO to AF7.

No
REPAIR the connection to C202a or C202c as necessary to the multifunction switch. TEST the system for normal operation.

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AF7 CARRY OUT A VOLTAGE DROP TEST ON THE BULB GROUND CIRCUITS

NOTE: Make sure to measure at all the lamps on the side of the concern.

NOTE: Make sure that there is some voltage drop when carrying out this step. There should always be some voltage drop. A voltage reading of 0 volts indicates that the test is being incorrectly carried out.

- Connect: Multifunction Switch C202a and C202c .
- Disconnect: LCM C2145d .

- NOTE: The bulb is shown removed for clarity. The bulb must be installed for correct test results.

- Connect a wire between the bulb and the ground terminal of the turn lamp.

- Connect a fused jumper wire between the LCM C2145d-23, circuit 195 (TN/WH), harness side and the LCM C2145d-24, circuit 44 (LB), harness side

- Place the multifunction switch in the LH or RH TURN position (the side that flashes fast).

- NOTE: The bulb is shown removed for clarity. The bulb must be installed for correct test results.

- Carry out a voltage drop test on the circuits between the suspect turn lamps and ground as follows:

- Is the voltage drop less than .2 volts?

Yes
REMOVE the jumper wires. GO to AF8.

No
REMOVE the jumper wires. REPAIR the ground circuit in question for high resistance. TEST the system for normal operation.

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AF8 CARRY OUT A VOLTAGE DROP TEST ON THE BULB POWER CIRCUITS

NOTE: Make sure to measure at all the lamps on the side of the concern.

- NOTE: The bulb is shown removed for clarity. The bulb must be installed for correct test results.

- Connect a wire between the bulb and the turn signal power terminal of the turn lamp.

- Connect a fused jumper wire between the LCM C2145d-23, circuit 195 (TN/WH), harness side and the LCM C2145d-24, circuit 44 (LB), harness side

- Is the voltage drop less than .2 volts?

Yes
REMOVE the jumper wires. INSTALL a new multifunction switch. REFER to Steering Column Switches Steering Column Multifunction Switch. TEST the system for normal operation.

No
REMOVE the jumper wires. REPAIR the power circuit in question for high resistance. TEST the system for normal operation.

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AF9 CHECK FOR CORRECT LCM OPERATION

- Disconnect all the LCM connectors.
- Check for:
- corrosion
- pushed-out pins
- Connect all the LCM 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 LCM. REFER to Multifunction Electronic Modules Service and Repair. 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.

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