Pinpoint Test F: The Auxiliary Audio Control Is Inoperative - Steering Wheel Switches
WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
- F1 CHECK THE STEERING WHEEL AUDIO CONTROL SWITCH CIRCUITS
- Key in OFF position.
- Disconnect: Audio Unit C290a.
- Measure the resistance between the audio unit C290a-18, circuit 595 (LB/RD), harness side and C290a-19 circuit 848 (DG/OG) harness side while pressing the steering wheel audio control buttons as follows:AUDIO UNIT RESISTANCE SPECIFICATION
Switch Resistance Range VOL Down 69.54-76.86 ohms VOL Up 195.89-216.51 ohms MEM 421.04-465.36 ohms MEDIA 851.39-941.01 ohms No Buttons Pressed 4,575.39-5,057.01 ohms - Are the resistances within specification?
- Yes : SEND the audio unit to an authorized repair facility. TEST the system for normal operation after the repair.
- No : GO to F3.
- F2 CHECK CIRCUIT 595 (LB/RD) FOR AN OPEN OR A SHORT TO GROUND
- Disconnect: Clockspring C218b.
- Measure the resistances between the audio unit C290a-18, circuit 595 (LB/RD), harness side and the clockspring C218b-3, circuit 595 (LB/RD), harness side; and between the audio unit C290a-18, circuit 595 (LB/RD), harness side and ground.
- Is the resistance less than 5 ohms between the audio unit and the clockspring, and greater than 10,000 ohms between the audio unit and ground?
- Yes : GO to F3.
- No : REPAIR the circuit. TEST the system for normal operation.
- F3 CHECK GROUND CIRCUIT 848 (DG/OG) FOR AN OPEN
- Measure the resistance between the clockspring C218b-5, circuit 848 (DG/OG), harness side and the audio unit C290a-19 circuit 848 (DG/OG), harness side.
- Is the resistance less than 5 ohms?
- Yes : GO to F4.
- No : REPAIR the circuit. TEST the system for normal operation.
- F4 CHECK THE STEERING WHEEL CONTROL SWITCH HARNESS FOR AN OPEN AND A SHORT TO GROUND
- Remove the driver air bag module. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Top of Clockspring.
- Examine the steering wheel controls harness for opens and shorts to ground.
- Is the steering wheel controls harness OK?
- Yes : GO to F5.
- No : REPAIR or INSTALL a new steering wheel controls harness. INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
- F5 ISOLATE AND CHECK THE SWITCHES
- Measure the resistance between the top of clockspring pin 4, harness side and the top of clockspring pin 2, harness side while pressing the steering wheel control buttons as follows:AUDIO UNIT RESISTANCE SPECIFICATION
Switch Resistance Range VOL Down 70-77 ohms VOL Up 196-217 ohms MEM 421-465 ohms MEDIA 851-941 ohms No Buttons Pressed 4,575-5,057 ohms - Are the resistances within specification?
- Yes : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
- No : INSTALL a new steering wheel control switch. REFER to AUDIO UNIT . INSTALL the driver air bag module. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation.
- Measure the resistance between the top of clockspring pin 4, harness side and the top of clockspring pin 2, harness side while pressing the steering wheel control buttons as follows: