Steering Wheel Audio Control Switch Does Not Operate

WARNING: This page is about a different car, the 2005 Infiniti G35. However, it is still accessible from the selected car via links, so may be relevant.

STEERING WHEEL AUDIO CONTROL SWITCH RESISTANCE CHECK
1. Turn ignition switch OFF.
2. Disconnect steering wheel audio control switch connector.
3. Check resistance steering wheel audio control switch. Refer to "Steering Wheel Audio Control Switch Resistance Check ".
  Resistance value is OK?
YES or NO
1. YES: GO TO 2.
2. NO: Replace steering wheel audio control switch.
STEERING WHEEL AUDIO CONTROL SWITCH CIRCUIT CHECK
1. Disconnect audio unit connector.
2. Check continuity between audio unit harness connector M39 and combination switch (spiral cable) harness connector M23.
  
  Fig 1: Audio Unit And Combination Switch Continuity Table
  Courtesy of NISSAN MOTOR CO., U.S.A.
  
  Fig 2: Checking Continuity Between Audio Unit Harness Connector And Combination Switch Harness Connector
  Courtesy of NISSAN MOTOR CO., U.S.A.
OK or NG
1. OK: GO TO 3.
2. NG: Repair harness or connector.
AUDIO UNIT CHECK
1. Connect audio unit connector.
2. Turn ignition switch ON.
3. Check voltage between audio unit harness connector M39 terminal 22 (R), 23 (G) and ground.
  22 (R) - Ground: Approx. 5V
  
  23 (G) - Ground: Approx. 5V
OK or NG
1. OK: Replace combination switch (spiral cable).
2. NG: Replace audio unit.
  
  Fig 3: Checking Voltage Between Audio Unit Harness Connector And Ground
  Courtesy of NISSAN MOTOR CO., U.S.A.