Steering Wheel Controls Malfunction
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Steering Wheel Controls Malfunction
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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12V Reference
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B1529 03, B1405 03
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1
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B1529 07
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B1529 07
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Steering Wheel Control Switch Signal
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1
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1
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B3622 07
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-
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1. Steering Wheel Controls Inoperative
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Circuit/System Description
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The body control module (BCM) supplies voltage to the audio steering wheel control switches and monitors the return signal. Each switch state is associated to a set resistance value and when pressed a specific voltage drop occurs across the resistor unique to the switch. The BCM identifies the switch selection and activates the feature.
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This diagnostic is for the audio steering wheel controls.
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Before diagnosis of the steering wheel controls, ensure the primary controls of the associated component are functioning properly.
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If a single switch function is inoperative, test the suspect switch. Refer to component testing.
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Schematic Reference
Steering Wheel Secondary/Configurable Control Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Steering Wheel Controls Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
for scan tool information
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1.
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Ignition OFF, disconnect the harness connector at the S70L Steering Wheel Controls Switch - Left and the S70R Steering Wheel Controls Switch - Right.
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2.
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Ignition ON, test for B+ between the voltage reference circuit terminal 1 and ground.
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3.
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If less than the specified value, test the voltage reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 body control module.
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4.
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Test for B+ between the voltage reference circuit terminal 1 and the signal circuit terminals listed below:
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Signal circuit terminal 6 - S70L Steering Wheel Controls Switch - Left
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Signal circuit terminal 2 - S70R Steering Wheel Controls Switch - Right
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5.
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If less than the specified value, test the signal circuits for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 body control module.
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6.
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Ignition OFF, disconnect the X3 harness connector at the K9 Body Control Module.
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7.
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Test for infinite resistance between the signal circuit terminals listed below and ground.
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Signal circuit terminal 6 - S70L Steering Wheel Controls Switch - Left
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Signal circuit terminal 2 - S70R Steering Wheel Controls Switch - Right
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8.
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If less than the specified value, test the signal circuit for a short to ground.
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9.
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Ignition ON, test for less than 0.3V between the signal circuit terminal 5 at the S70R Steering Wheel Controls Switch - Right and ground.
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10.
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If greater than the specified range, test the signal circuit for a short to voltage.
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11.
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Test for infinite resistance between the signal circuit terminal 5 at the S70R Steering Wheel Controls Switch - Right and ground.
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12.
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If not the specified value, test the signal circuit for a short to ground.
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13.
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Test for less than 5 Ω between the signal circuit terminal 5 at the S70R Steering Wheel Controls Switch - Right and the signal circuit terminal 5 at the S70L Steering Wheel Controls Switch - Left.
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14.
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If greater than the specified range, test the signal circuit for an open/high resistance.
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15.
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If all circuits test normal, test or replace the S70R Steering Wheel Controls Switch - Right or S70L Steering Wheel Controls Switch - Left.
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Static Test
Right Steering Wheel Switch
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1.
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Disconnect the harness connector at the S70R Steering Wheel Controls Switch - Right.
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2.
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Test the resistance between the terminals 1 and 2 of the S70R Steering Wheel Controls Switch - Right.
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3.
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If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the S70R Steering Wheel Controls Switch - Right.
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Function Switch
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Minimum Resistance Value
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Maximum Resistance Value
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Mute/End
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1.0 kΩ
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1.4 kΩ
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Voice Recognition/Phone
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1.3 kΩ
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1.7 kΩ
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Volume Up
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1.7 kΩ
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2.1 kΩ
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Volume Down
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2.2 kΩ
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2.6 kΩ
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Next
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2.8 kΩ
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3.2 kΩ
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Previous
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3.6 kΩ
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4.0 kΩ
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No Switch Pressed
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O.L.
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O.L.
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Left Steering Wheel Switch
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1.
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Disconnect the harness connector at the S70L Steering Wheel Controls Switch - Left.
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2.
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Test the resistance between the terminals 5 and 6 of the S70L Steering Wheel Controls Switch - Left.
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3.
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If any of the resistance measurements for the individual switches are not within the specified resistance values, replace the S70R Steering Wheel Controls Switch - Right.
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Function Switch
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Minimum Resistance Value
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Maximum Resistance Value
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Source
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1.3 kΩ
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1.7 kΩ
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No Switch Pressed
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O.L.
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O.L.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
