Checking the Audio/Carphone Switch

Checking the audio/carphone switch

Checking components and wiring

Is the car equipped with the Road Traffic Information (RTI) system?

Yes - Checking components and wiring 1

No - Checking components and wiring 2

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Checking components and wiring 1

- Ignition off
- Disconnect the RTI switch
- Ignition on.
Activate and read off the status of the buttons in the audio/carphone switch.
If the readings give a correct result, the fault is in the RTI switch.

Other information:
- To access the RTI switch, see RTI switch RTI Switch.

Was the audio/carphone switch status OK?

Yes - Troubleshooting complete

No - Checking components and wiring

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Checking components and wiring 2

- Ignition off
- Disconnect the audio/carphone switch by disconnecting the lower connector on the audio/carphone switch
- Ignition on.
Activate the buttons. Read off the status of the buttons in the cruise control switch
If the readings give a correct result, the fault is in the audio/carphone switch.

Other information:
- To access the audio/carphone switch, see Keypad steering wheel, replacing, TF-80SC AWD, AW50/51 AWD, M66 AWD Keypad Steering Wheel, Replacing.

- Ignition off
- Disconnect the audio/carphone wiring by disconnecting the lower connector on the cruise control switch
- Ignition on.
Activate the buttons. Read off the status of the buttons in the cruise control switch
If the readings give a correct result, the fault is in the wiring between the audio/carphone switch and the cruise control switch.

Other information:
- To access the cruise control switch, see Keypad steering wheel, replacing, TF-80SC AWD, AW50/51 AWD, M66 AWD Keypad Steering Wheel, Replacing.

Was the status of the cruise control switch OK?

Yes - Troubleshooting procedure complete

No - Checking components and wiring

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Checking components and wiring
Check the voltage between terminals #B1 and #B3. Voltage must be approximately 12 V.
Check the voltage between terminals #B2 and #B3. Voltage must be approximately 5 V.
Check the voltage between terminal #B3 and the battery negative terminal. Voltage must be approximately 0 V.
If the above readings are OK, the fault is in the cruise control switch.

Other information:
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box.

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