• Garry's Mustang Help
    COURTESY LAMPS
    INOPERATIVE
  • AA1 CHECK FUSE FOR VOLTAGE
    • Using a test lamp, check the output side of fuse 8 (10A) for volts
    • - Did test lamp illuminate?
      • Yes
      • GO TO AA3
      • No
      • GO TO AA2
  • AA2 CHECK CIRCUIT FOR SHORT
    • - Remove fuse 8 (10A)
    • - Connect one lead of an ohmeter to a known good ground, connect second lead to output side of fuse 8 (10A). Measure Resistance.
    • - Is resistance 5 ohms or less?
      • Yes
      • SERVICE, Circuit 54 (LG/Y) for short to ground. Restore vehicle. RETEST system. REPLACE fuse 8 (10A).
      • No
      • GO to AA3
  • AA3 CHECK VOLTAGE AT SWITCHES
    • -Remove courtesy lamp switch (13713) at each door (4005A26). (If sedan, remove courtesy lamp switch at rear door (24631) also.) Leave courtesy lamp switch connected to harness.
    • - Using a test lamp connected to a known good ground, check Circuit 54 (LG/Y) for voltage at each courtesy lamp switch.
    • - Is voltage present at all courtesy lamp switches?
      • Yes
      • GO TO AA4
      • No
      • SERVICE Circuit 54(LG/Y) at suspect courtesy lamp switch for open circuit. RESTORE vehicle. RETEST system.
  • AA4 CHECK COURTESY LAMP SWITCHES
    • - Disconnect courtesy lamp switches.
    • - Using an ohmeter, check for continuity at all switch terminals of each courtesy lamp switch.
    • - Is there continuity?
      • Yes
      • GO TO AA5
      • No
      • REPLACE courtesy lamp switch. RESTORE vehicle. RETEST system.
  • AA5 CHECK HEADLAMP SWITCH SUPPLY
    • - Remove headlamp switch. Leave headlamp switch connected
    • - Using voltmeter, test terminal D1 Circuit 54(LG/Y) for voltage.
    • - Is voltage present?
      • Yes
      • GO TO AA6
      • No
      • SERVICE Circuit 54(LG/Y) for open circuit. RESTORE vehicle. RETEST system.
  • AA6 CHECK HEADLAMP SWITCH OUTPUT
    • - Remove voltmeter from terminal D1 and connect it to terminal D2 Circuit 706(GY).
    • - Turn headlamp switch couterclockwise to the stop.
    • - Is voltage present?
      • Yes
      • SERVICE Circuit 53(BK/BL) for open. RESTORE vehicle. RETEST system.
      • No
      • REPLACE headlamp switch. RESTORE vehicle. RETEST system.
  • Garry's Mustang Help
    CHARGE INDICATOR
    FAULTY
  • E1- LAMP CHECK NO.1
    • Engine OFF, Key in OFF position.
    • - Is charge indicator on?
      • Yes
      • Refer to Section 14-00 SERVICE as necessary
      • No
      • Go to E2.
  • E2- LAMP CHECK NO.2
    • Engine OFF, Key in RUN position.
    • - Is charge indicator on?
      • Yes
      • Go to E3
      • No
      • Go to E4.
  • E3- LAMP CHECK NO.3
    • Key in RUN position, Engine RUNNING
    • - Is charge indicator on?
      • Yes
      • Go to E6
      • No
      • Lamp test complete and operational.
  • E4- INOPERATIVE INDICATOR LAMP
    • Key in ON position, Engine OFF
    • Disconnect regulator connector and ground "I" terminal.
    • - Is charge indicator on?
      • Yes
      • REFER to Section 14-02. SERVICE as necessary.
      • No
      • Go to E5.
  • E5- CHECK CIRCUIT 904(LG/R) FOR OPEN
    • Turn ignition switch to the OFF position. Engine OFF
    • Remove instrument cluster.
    • Using an ohmmeter connected to a known good ground, connect second lead to pin 10 Circuit 904(LG/R).
    • Measure resistance.
    • - Is resistance 5 ohms or less?
      • Yes
      • REMOVE jumper wire. Go to E6.
      • No
      • SERVICE circuit 904(LG/R) for open circuit. RESTORE vehicle. RETEST system.
  • E6- CHECK CIRCUIT 904(LG/R) FOR SHORT
    • Disconnect instrument cluster connectors.
    • Disconnect voltage regulator connector.
    • Using an ohmmeter connected to a known good ground, connect second lead to pin 10 Circuit 904(LG/R).
    • Measure resistance.
    • - Is resistance 5 ohms or less?
      • Yes
      • SERVICE circuit 904(LG/R) for open circuit. RESTORE vehicle. RETEST system.
      • No
      • Go to E7.
  • E7- CHECK CIRCUIT16(R/LG) FOR VOLTAGE
    • Turn ignition switch to the RUN position.
    • Using a test lamp connectec to a known good ground, connect other end to pin 11 circuit 16(R/LG).
    • - Did test lamp illuminate?
      • Yes
      • Go to E8.
      • No
      • SERVICE circuit 16(R/LG) for open circuit. RESTORE vehicle. RETEST system.
  • E8- CHECK CHARGE INDICATOR LAMP
    • Remove charge indicator lamp bulb.
    • Using an ohmmeter, check continuity of bulb
    • - Is bulb continuity OK?
      • Yes
      • REPLACE instrument cluster printed circuit. RESTORE vehicle. RETEST system.
      • No
      • REPLACE damaged bulb. RESTORE vehicle. RETEST system.