Steering wheel controls
Steering wheel controls |
General |
The audio system can also be operated with the steering wheel controls (control buttons on the steering wheel). The steering wheel controls which are used for the audio system comprise 2 units (6 switches). Full instructions for their use are given in the owner's manual.
The steering wheel switches are connected to SID control module which communicates information defining which switches are active. SID sends information about the buttons on the bus which is then read by the head unit.
Function |
The SID control module supplies +5V to the steering wheel controls via pin 25 and grounds them via pin 26.
The steering wheel control switches incorporate resistors connected in series. When a button is pressed, the activated switch is grounded, see the table.
The value of the total resistance in the circuit changes according to which switch is depressed and there is a corresponding change in the voltage which is sensed by the SID control module.
Diagnosis |
If there is an open or short circuit to B+ or short circuit to ground for more than 5 minutes, the SID will generate diagnostic trouble code B2371.
Switch
|
Function
|
Voltage (V)
|
Resistance (Ohms)
|
VOL -
|
Reduce volume
|
1.3
|
78
|
VOL +
|
Increase volume
|
1.7
|
117
|
SRC
|
Selection of audio source
|
2.1
|
167
|
Arrow up
|
Search forwards
|
2.5
|
234
|
Arrow down
|
Search backwards
|
2.9
|
327
|
NXT
|
Preset radio tuning/
compact disc |
3.3
|
467
|
Normal
|
No button pressed
|
4,5
|
2563
|