Pinpoint Test G: The Auxiliary Audio Control Is Inoperative - Steering Wheel Audio Control Switch(Es)
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
- G1 CHECK THE STEERING WHEEL AUDIO CONTROL SWITCH CIRCUITS
- Key in OFF position.
- Disconnect: Audio Unit.
- Measure the resistance between the audio unit C240a-14 (DM100) or C290a-18 (CD6), circuit 583 (YE), harness side and ground while pressing the steering wheel audio control buttons as follows:SWITCH RESISTANCE RANGES
Switch Resistance Range VOL Down 69.27-77.38 ohms VOL Up 198.5-217.61 ohms NEXT 419.4-467.5 ohms MODE 848.1-945.1 ohms No Buttons Pressed 4,560-5,080 ohms - Are the resistances within specification?
- Yes : SEND the audio unit to an authorized audio system repair facility. TEST the system for normal operation after the repair.
- No : GO to G2.
- G2 CHECK CIRCUIT 583 (YE) FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Clockspring C218a.
- Measure the resistances between the audio unit C24Da-i4 (DM100), or C290a-18 (CD6), circuit 583 (YE), harness side and the clockspring C218a-3, circuit 583 (YE), harness side; and between the audio unit C240a-14 (DM100), or C290a-18 (CD6), circuit 583 (YE), 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 G3.
- No : REPAIR the circuit. TEST the system for normal operation.
- G3 CHECK THE GROUND CIRCUIT 848 (DG/OG)
- Measure the resistance between the clockspring C218a-5, circuit 848 (DG/OG), harness side and ground.
- Is the resistance less than 5 ohms?
- Yes : GO to G4.
- No : GO to G6.
- G4 CHECK THE SIGNAL CIRCUIT IN THE STEERING WHEEL CONTROL SWITCH HARNESS
- Remove the driver air bag. Refer to SUPPLEMENTAL RESTRAINT SYSTEM .
- Disconnect: Steering Wheel Control Switch Harness.
- Measure the resistance between the steering wheel control switch C2983, pin 4, circuit 583 (YE), harness side and the steering wheel control switch harness pin 3, circuit 583 (YE), harness side.
- Is the resistance less than 5 ohms?
- Yes : GO to G5.
- No : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation. INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
- G5 CHECK THE GROUND CIRCUIT IN THE STEERING WHEEL CONTROL SWITCH HARNESS
- Measure the resistance between the steering wheel control switch C2983, pin 3 circuit 848 (DG/OG), harness side and the steering wheel control switch harness pin 5, circuit 848 (DG/OG), component side.
- Is the resistance less than 5 ohms?
- Yes : INSTALL a new steering wheel control audio switch. REFER to AUDIO UNIT . TEST the system for normal operation. INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
- No : INSTALL a new clockspring. REFER to SUPPLEMENTAL RESTRAINT SYSTEM . TEST the system for normal operation. INSTALL the air bag. REFER to SUPPLEMENTAL RESTRAINT SYSTEM .
- G6 CHECK CIRCUIT 848 (DG/OG) FOR AN OPEN
- Disconnect: Powertrain Control Module (PCM) C175b.
- Measure the resistance between the clockspring C218a-5, circuit 848 (DG/OG), harness side and the PCM C175b-30, circuit 848 (DG/OG), harness side
- Is the resistance less than 5 ohms?
- Yes : GO to G7.
- No : REPAIR the circuit. TEST the system for normal operation.
- G7 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
- corrosion.
- pushed-out pins.
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS . CLEAR the DTCs. REPEAT the PCM self-test.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.