Ford Mustang Service Manual: Ignition Switch

Steering Column Switches (Diagnosis and Testing)

Refer to Wiring Diagrams Cell 13 , Power Distribution for schematic and connector information.

Refer to Wiring Diagrams Cell 81 , Interval Wiper/Washer for schematic and connector information.

Refer to Wiring Diagrams Cell 85 , Headlamps for schematic and connector information.

Refer to Wiring Diagrams Cell 90 , Turn/Stop/Hazard Lamps for schematic and connector information.

Special Tool(s)



Worldwide Diagnostic System Worldwide Diagnostic System (WDS) 418-F224, New Generation STAR (NGS) Tester 418-F052, or equivalent scan tool
73 Digital Multimeter 73 Digital Multimeter 105-R0051 or equivalent

Inspection and Verification

1. Verify the customer concern by operating the multifunction or ignition switch.

2. Visually inspect for obvious signs of mechanical and electrical damage.

Visual Inspection Chart

Mechanical

Electrical

  • Ignition key

  • Ignition switch

  • Multifunction switch

  • Turn signal switch

  • Hazard/flasher switch
  • Battery junction box (BJB) Fuses:
  • (3) IGN (40A)
  • Central junction box (CJB) Fuses:
  • 6 (25A)
  • 39 (5A)
  • Damaged wiring harness
  • Loose or corroded connections

3. If the concern remains after the inspection, connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from the scan tool menu. If the scan tool does not communicate with the vehicle:

  • check that the program card is correctly installed.
  • check the connections to the vehicle.
  • check the ignition switch position.

4. If the scan tool still does not communicate with the vehicle, refer to the scan tool manual.

5. Carry out the DATA LINK DIAGNOSTIC TEST. If the scan tool responds with:

  • CKT914, CKT915 or CKT70 =ALL ECUS NO RESP/NOT EQUIP
  • NO RESP/NOT EQUIP for GEM, go to Pinpoint Test A.
  • SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the GEM.

6. If the DTCs retrieved are related to the concern, go to the GEM Diagnostic Trouble Code (DTC) Index to continue diagnostics.

7. If no DTCs related to the concern are retrieved, proceed to the Symptom Chart to continue diagnostics.

GEM Diagnostic Trouble Code (DTC) Index

DTC Description Source
B1217 Horn Relay Coil Circuit Failure GEM
B1218 Horn Relay Coil Circuit Short to Vbatt GEM
B1312 Lamp Headlamp Input Circuit Short to Battery GEM
B1317 Battery Voltage High GEM
B1318 Battery Voltage Low GEM
B1322 Driver Door Ajar Circuit Short to Ground GEM
B1330 Passenger Door Ajar Circuit Short to Ground GEM
B1334 Decklid Ajar Rear Door Circuit Short to Ground GEM
B1339 Chime Input Request Circuit Short to Battery GEM
B1340 Chime Input Request Circuit Short to Ground GEM
B1342 ECU Is Defective GEM
B1353 Ignition Key-In Circuit Open GEM
B1359 Ignition Run/Acc Circuit Failure GEM
B1396 Power Door Lock Circuit Short to Battery GEM
B1397 Power Door Unlock Circuit Short to Battery GEM
B1405 Driver Power Window Down Circuit Short to Battery GEM
B1408 Driver Power Window Up Circuit Short to Battery GEM
B1410 Driver Power Window Motor Circuit Failure GEM
B1426 Lamp Safety Belt Circuit Short to Battery GEM
B1428 Lamp Safety Belt Circuit Failure GEM
B1431 Wiper Brake/Run Relay Circuit Failure GEM
B1432 Wiper Brake/Run Relay Circuit Short to Battery GEM
B1434 Wiper Hi/Low Speed Relay Coil Circuit Failure GEM
B1436 Wiper Hi/Low Speed Relay Coil Circuit Short to Battery GEM
B1438 Wiper Mode Select Switch Circuit Failure GEM
B1441 Wiper Mode Select Switch Circuit Short to Ground GEM
B1446 Wiper Park Sense Circuit Failure GEM
B1448 Wiper Park Sense Circuit Short to Battery GEM
B1450 Wiper Wash/Delay Switch Circuit Failure GEM
B1453 Wiper Wash/Delay Switch Circuit Short to Ground GEM
B1458 Wiper Washer Pump Motor Relay Circuit Failure GEM
B1460 Wiper Washer Pump Motor Relay Coil Circuit Short to Battery GEM
B1462 Safety Belt Switch Circuit Failure GEM
B1466 Wiper Hi/Low Speed Not Switching GEM
B1473 Wiper Low Speed Circuit Motor Failure GEM
B1476 Wiper High Speed Circuit Motor Failure GEM
B1551 Decklid Release Circuit Failure GEM
B1553 Decklid Release Circuit Short to Battery GEM
B1555 Ignition Run/Start Circuit Failure GEM
B1687 Lamp Dome Input Circuit Short to Battery GEM
B2486 LF Side Repeater Lamp Output Circuit Failure GEM
B2488 RF Side Repeater Lamp Output Circuit Failure GEM
C1189 Brake Fluid Level Sensor Input Short Circuit to Ground GEM
C1223 Lamp Brake Warning Output Circuit Failure GEM
C1225 Lamp Brake Warning Output Circuit Short to Battery GEM

Symptom Chart

Condition Possible Sources Action
  • No communication with the generic electronic module
  • CJB Fuse 39 (5A).
  • Circuitry.
  • GEM.
  • Go To Pinpoint Test A .
  • The ignition switch is inoperative
  • BJB Fuse IGN SW (40A).
  • Ignition switch.
  • Circuitry.
  • Go To Pinpoint Test B .
  • No power in ACC
  • Ignition switch.
  • Circuitry.
  • Go To Pinpoint Test C .
  • No power in RUN
  • Ignition switch.
  • Circuitry.
  • Go To Pinpoint Test D .
  • No power in START
  • Ignition switch.
  • Circuitry.
  • Go To Pinpoint Test E .
  • The multifunction switch/hazard switch does not operate correctly
  • Multifunction switch.
  • Carry out the multifunction switch component test.

    REFER to Wiring Diagrams, Cell 149, Component Testing.

Pinpoint Tests

PINPOINT TEST A: NO COMMUNICATION WITH THE GENERIC ELECTRONIC MODULE

Test Step Result / Action to Take
CAUTION: Use the correct probe adapter(s) when making measurements. Filaure to use the correct probe adapter(s) may damage the connector.
A1 CHECK THE GENERIC ELECTRONIC MODULE (GEM) POWER SUPPLY Yes

GO to A2 .

No

REPAIR the circuit(s) in question. TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: Generic Electronic Module (GEM) C201a.
  • Disconnect: GEM C201b.
  • Key in ON position.
  • Using the following table. measure the voltage between the GEM, harness side and ground.


  • Are the voltages greater than 10 volts?
A2 CHECK THE GEM GROUND CIRCUIT 397 (BK/WH) FOR OPEN Yes

GO to A3 .

No

REPAIR the circuit(s) in question. TEST the system for normal operation.
  • Key in OFF position.
  • Measure the resistance between the GEM C201b pin 2, circuit 397 (BK/WH), harness side and ground.


  • Is the resistance less than 5 ohms?
A3 CHECK CIRCUIT 397 (BK/WH) FOR SHORT TO POWER Yes

REPAIR the circuit. TEST the system for normal operation.

No
  • Measure the voltage between GEM C201b pin 2, circuit 397 (BK/WH), harness side and ground.


  • Is any voltage present?

PINPOINT TEST B: THE IGNITION SWITCH IS INOPERATIVE

Test Step Result / Action to Take
B1 CHECK THE IGNITION SWITCH Yes

INSTALL a new BJB. TEST the system for normal operation.

No

INSTALL a new ignition switch. REFER to Ignition Switch . TEST the system for normal operation.
  • Carry out the ignition switch component test.

    REFER to Wiring Diagrams Cell 149, Component Testing.

  • Is the ignition switch OK ?

PINPOINT TEST C: NO POWER IN ACC

Test Step Result / Action to Take
C1 CHECK THE RADIO FOR NORMAL OPERATION Yes

GO to C2 .

No

Go To Pinpoint Test D .
  • Key in ON position.
  • Check the radio for normal operation.
  • Does the radio operate correctly?
C2 CHECK THE VOLTAGE AT THE IGNITION SWITCH Yes

INSTALL a new ignition switch. REFER to Ignition Switch . TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation.
  • Disconnect: Ignition Switch C250 .
  • Measure the voltage between ignition switch C250 Pin B5, Circuit 1050 (LG/VT), harness side and ground.


  • Is the voltage greater than 10 volts?

PINPOINT TEST D: NO POWER IN RUN

Test Step Result / Action to Take
D1 CHECK THE IGNITION SWITCH Yes

INSTALL a new BJB. TEST the system for normal operation.

No

INSTALL a new ignition switch. REFER to Ignition Switch . TEST the system for normal operation.
  • Carry out the ignition switch component test.

    REFER to Wiring Diagrams Cell 149, Component Testing.

  • Is the ignition switch OK ?

PINPOINT TEST E: NO POWER IN START

Test Step Result / Action to Take
E1 CHECK THE VOLTAGE TO THE IGNITION SWITCH Yes

GO to E2 .

No

REPAIR the circuit in question.TEST system for normal operation.
  • Key in OFF position.
  • Disconnect: Ignition Switch C250 .
  • Measure the voltage between ignition switch C250 Pin B4, Circuit 1050 (LG/VT), harness side and ground; and between ignition switch C250 Pin B5, Circuit 1050 (LG/VT), harness side and ground.


  • Are the voltages greater than 10 volts?
E2 CHECK THE CONTINUITY OF THE IGNITION SWITCH Yes

GO to E3 .

No

INSTALL a new ignition switch. REFER to Ignition Switch . TEST the system for normal operation.
  • Carry out the ignition switch continuity test. REFER to Wiring Diagrams, Cell 149, Component Testing.
  • Does the ignition switch test OK?
E3 CHECK CIRCUIT 16 (RD/LB), AND CIRCUIT 33 (WH/PK) Yes

REPAIR Circuit 16 (RD/LB). TEST the system for normal operation.

No

REPAIR Circuit 33 (WH/PK). TEST the system for normal operation.
  • Connect: Ignition Switch C250.
  • Turn ignition switch to START.
  • Does the starter engage?

Component Test

Ignition Switch Continuity Check

Refer to Wiring Diagrams Cell 149, Component Testing.

Multifunction Switch

Refer to Wiring Diagrams Cell 149, Component Testing.

    Multifunction Switch
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