Pinpoint Test D: The Steering Wheel Switch Illumination Is Inoperative

Instrument Cluster and Panel Illumination

Pinpoint Test D: The Steering Wheel Switch Illumination Is Inoperative

Normal Operation

The BCM (Body Control Module) sends a voltage to the steering wheel controls switch and message center switch based on the Steering Column Control Module (SCCM) illumination messages that are sent over the network to the BCM (Body Control Module). The voltage passes through the clockspring to the steering wheel harness and on to the steering wheel switches. The steering wheel switches share the ground circuit with the horn switch.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Message center switch

- Steering wheel controls switch

- Steering wheel harness

- Clockspring

PINPOINT TEST D : THE STEERING WHEEL SWITCH ILLUMINATION IS INOPERATIVE

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

D1 CHECK THE OTHER DIMMABLE LIGHTING SWITCHES

- Ignition OFF.

- Place the headlamp switch in the PARKING LAMPS ON position.

- Press and hold the instrument panel dimmer switch to the first detent up to the full illumination position and observe other dimmable switches.

Are all the dimmable switches inoperative?

Yes
GO to Pinpoint Test B. Pinpoint Test B: All Dimmable Non-Networked Illumination Is Inoperative
No
GO to D2.

D2 CHECK THE HORN OPERATION

- Press the driver air bag module against the steering wheel.

Does the horn sound?

Yes
GO to D3.

No
REFER to Horn to diagnose the horn is inoperative.

D3 CHECK FOR VOLTAGE TO THE STEERING WHEEL SWITCH

- Place the headlamp switch in the OFF position.

- Disconnect: Inoperative Steering Wheel Switch.

- Place the headlamp switch in the PARKING LAMPS ON position.

- Press and hold the instrument panel dimmer switch to the first detent up to the full illumination position.

- For the message center switch, measure the voltage between the message center switch C2998-4, circuit VLN04 (BN), harness side and the message center switch C2998-3, circuit GD185 (GN/TN), harness side.





- For the steering wheel controls switch, measure the voltage between the steering wheel controls switch C2999-6, circuit VLN04 (BN), harness side and the steering wheel controls switch C2999-1, circuit GD185 (GN/TN), harness side.





Is the voltage greater than 10 volts?

Yes
REPLACE the inoperative steering wheel switch.

For the message center switch, REFER to Instrument Panel, Gauges and Warning Indicators.

For the steering wheel controls switch, REFER to Accessories and Optional Equipment. TEST the system for normal operation.

No
GO to D4.

D4 CHECK FOR VOLTAGE TO THE CLOCKSPRING

- Place the headlamp switch in the OFF position.

- Disconnect: Clockspring C218A.

- Place the headlamp switch in the PARKING LAMPS ON position.

- Measure the voltage between the clockspring C218A-9, circuit VLN04 (VT/GY), harness side and ground.





Is the voltage greater than 10 volts?

Yes
GO to D5.

No
REPAIR circuit VLN04 (VT/GY) for an open. TEST the system for normal operation.

D5 CHECK THE GROUND CIRCUIT TO THE CLOCKSPRING FOR CONTINUITY

- Measure the voltage between the clockspring C218A-9, circuit VLN04 (VT/GY), harness side and the clockspring C218A-8, circuit GD185 (BK), harness side.





Is the voltage greater than 10 volts?

Yes
GO to D6.

No
REPAIR circuit GD185 (BK) for an open. TEST the system for normal operation.

D6 CHECK FOR VOLTAGE TO THE UPPER CLOCKSPRING

- Connect: Clockspring C218A.

- Disconnect: Clockspring C218B.

- Measure the voltage between the clockspring C218B-9, component side and the clockspring C218A-10, component side.





Is the voltage greater than 10 volts?

Yes
INSTALL a new steering wheel. TEST the system for normal operation.

No
INSTALL a new clockspring. TEST the system for normal operation.