Ford Mustang Quiz
Instrumentation and Warning Systems

Pinpoint Tests

In this manual: Instrumentation and Warning Systems
Service Information — 34Suspension — 63Driveline — 80Brake System — 74Steering System — 42Engine — 329Automatic Transmission — 84Manual Transmission, Clutch and Transfer Case — 64Exhaust System — 8Fuel System — 39Climate Control System — 76Instrumentation and Warning Systems — 25Battery and Charging System — 19Audio Systems — 14Lighting — 24Electrical Distribution — 8Electronic Feature Group — 11Body — 173Frame and Mounting — 6General Information — 1
~4min read

PINPOINT TEST A: THE CONTROL ILLUMINATION IS INOPERATIVE

Test Step Result / Action to Take
A1 CHECK PARKING LAMPS Yes

Place the headlamp switch in the OFF position.

GO to A2 .

No

REFER to Section.
  • Place the headlamp switch in the ON position.
  • Are the exterior lamps on?
A2 CHECK HEADLAMP SWITCH Yes

RECONNECT the headlamp switch. GO to A3 .

No

INSTALL a new headlamp switch. REFER to Section. TEST the system for normal operation.
  • Key in OFF position.
  • Carry out the headlamp switch components test; Refer to Wiring Diagrams Cell 149 for schematic and connector information.
  • Is the headlamp switch OK?
A3 CHECK CIRCUIT 1045 (DB/WH) Yes

REPAIR circuit 19 (LB/RD). TEST the system for normal operation.

No

REPAIR circuit 1045 (DB/WH). TEST the system for normal operation.
  • Place the headlamp switch in the ON position.
  • Rotate the instrument panel dimmer switch to the full illumination position.
  • Measure voltage between central junction box (CJB) fuse 37 (5A) and ground.
  • Is the voltage greater than 10 volts?

PINPOINT TEST B: THE INSTRUMENT CLUSTER ILLUMINATION IS INOPERATIVE

Test Step Result / Action to Take
B1 CHECK VOLTAGE TO INSTRUMENT CLUSTER ILLUMINATION Yes

GO to B2 .

No

REPAIR the circuit. TEST the system for normal operation.
  • Disconnect: Instrument Cluster .
  • Place the headlamp switch in the ON position.
  • Rotate the instrument panel dimmer switch to the full illumination position.
  • Measure the voltage between the instrument cluster C220b pin 4, circuit 19 (LB/RD), harness side and ground.
  • Is the voltage greater than 10 volts?
B2 CHECK GROUND TO INSTRUMENT CLUSTER Yes

INSTALL a new instrument cluster. REFER to Section. TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation.
  • Place the headlamp switch in the OFF position.
  • Measure the resistance between the instrument cluster C220b pin 1, circuit 1205 (BK), harness side and ground.
  • Are the resistances less than 5 ohms?

PINPOINT TEST C: THE CLIMATE CONTROL ILLUMINATION IS INOPERATIVE

Test Step Result / Action to Take
C1 CHECK VOLTAGE TO CLIMATE CONTROL ILLUMINATION Yes

GO to C2 .

No

REPAIR the circuit.

TEST the system for normal operation.
  • Disconnect: Function Selector Switch C294b .
  • Place the headlamp switch in the ON position.
  • Rotate the instrument panel dimmer switch to the full illumination position.
  • Measure the voltage between the function selector switch C294b pin 2, circuit 19 (LB/RD), harness side and ground.
  • Is the voltage greater than 10 volts?
C2 CHECK GROUND TO CLIMATE CONTROL Yes

INSTALL new illumination bulb(s).

REFER to Section .

No

REPAIR the circuit.

TEST the system for normal operation.
  • Measure the resistance between the function selector switch C294b pin 1, circuit 1205 (BK), harness side and ground.
  • Is the resistance less than 5 ohms?

PINPOINT TEST D: THE AUDIO SYSTEM ILLUMINATION IS INOPERATIVE

Test Step Result / Action to Take
D1 CHECK VOLTAGE TO AUDIO UNIT Yes

GO to D2 .

No

REPAIR the circuit. TEST the system for normal operation.
  • Disconnect: Audio Unit C290a.
  • Place the headlamp switch in the ON position.
  • Rotate the instrument panel dimmer switch to the full illumination position.
  • Measure the voltage between the audio unit C290a pin 1, circuit 19 (LB/RD), harness side and ground.
  • Is the voltage greater than 10 volts?
D2 CHECK GROUND TO AUDIO UNIT Yes

REMOVE the audio unit and SEND it to an authorized Ford audio systems repair facility.

TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation.
  • Measure the resistance between the audio unit C290a pin 2, circuit 1205 (BK), harness side and ground.
  • Is the resistance less than 5 ohms?

PINPOINT TEST E: A SINGLE ILLUMINATION SOURCE IS INOPERATIVE

Test Step Result / Action to Take
E1 CHECK VOLTAGE TO THE SINGLE ILLUMINATION SOURCE Yes

GO to E2 .

No

REPAIR the circuit. TEST the system for normal operation.
  • Disconnect: Inoperative Illumination Source.
  • Place the headlamp switch in the ON position.
  • Rotate the instrument panel dimmer switch to the full illumination position.
  • Measure the voltage between the inoperative illumination source, circuit 19 (LB/RD), harness side and ground.
  • Is the voltage greater than 10 volts?
E2 CHECK SINGLE ILLUMINATION SOURCE GROUND Yes

INSTALL a new component in question. TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation.
  • Measure the resistance between inoperative illumination source, circuit 1205 (BK), harness side and ground.
  • Is the resistance less than 5 ohms?

Instrument Cluster Bulb

Removal and Installation

1. Remove the instrument cluster. For additional information, refer to Section.

2. Remove the necessary instrument cluster bulbs by rotating the bulb one quarter turn counterclockwise and lifting straight out of the instrument cluster.

Instrument Cluster Bulb

3. To install, reverse the removal procedure.

Test yourself

A quick Ford Mustang quiz: every answer comes with an explanation and a link to the manual page.