Ford Mustang (1999-2004) Service Manual: Symptom Chart

Condition Possible Sources Action
  • Incorrect/erratic direction of airflow from outlet(s)
  • No vacuum to A/C heater function switch selector.
  • A/C heater function selector switch leaks vacuum.
  • Kinked/pinched vacuum hose.
  • Leaking vacuum control motor.
  • Leaking A/C vacuum check valve.
  • Leaking A/C vacuum reservoir tank and bracket.
  • Vacuum actuator arm not connected to door crank.
  • Go To Pinpoint Test A .
  • Insufficient, erratic, or no heat
  • Low engine coolant level.
  • Thermostat stuck open.
  • Disengaged/damaged temperature cable.
  • Go To Pinpoint Test B .
  • Insufficient, erratic, or no heat
  • CASS strategy failure.
  • Open fuses.
  • A/C clutch relay.
  • Shorted blend door actuator.
  • Powertrain control module.
  • Circuitry short/open.
  • A/C cycling switch damaged.
  • A/C system discharged/low charge.
  • Function selector switch damaged.
  • A/C pressure cut-off switch damaged.
  • A/C compressor clutch damaged.
  • Go To Pinpoint Test C .
  • The A/C is always on
  • Circuitry short/open.
  • A/C cycling switch.
  • A/C heater function selector switch.
  • Constant control relay module.
  • Incorrect A/C clutch air gap.
  • Go To Pinpoint Test D .
  • Insufficient A/C cooling
  • Restricted A/C evaporator core orifice.
  • Low refrigerant level.
  • Go To Pinpoint Test E .
  • No operation in all the temperature settings
  • Damaged blend door actuator cable.
  • Damaged air temperature control door.
  • Go To Pinpoint Test F
  • The blower motor does not operate
  • Open fuse.
  • Circuitry open/shorted.
  • Damaged heater blower motor switch (18578).
  • Damaged heater blower motor switch resistor (18591).
  • Damaged blower motor relay.
  • Damaged blower motor
  • Go To Pinpoint Test G .
  • The blower motor operates continuously in high speed
  • Circuitry short/open.
  • Damaged heater blower motor switch resistor.
  • Damaged heater blower motor switch.
  • Go To Pinpoint Test H .
  • No operation in high blower setting
  • Circuitry short/open.
  • Damaged heater blower motor switch.
  • Go To Pinpoint Test I .
  • No operation in lower speeds
  • Circuitry short/open.
  • Damaged heater blower motor switch resistor.
  • Damaged heater blower motor switch.
  • Go To Pinpoint Test J .
    Inspection and Verification
    1. Verify the customer's concern by operating the climate control system to duplicate the condition. 2. Inspect to determine if one of the following mechanical or electrical concerns apply: Visu ...

    Pinpoint Tests
    PINPOINT TEST P1464: DTC P1464: A/C DEMAND OUT OF SELFTEST RANGE Test Step Result / Action to Take P14641 RECHECK FOR THE DTC YesGO to P14642 . No The system is functioning correc ...

    Other materials:

    Anti-theft system
    The active anti-theft system is designed to warn you in the event of unauthorized vehicle entry and is also designed to help prevent unwanted towing of the vehicle. You can choose what is monitored by arming the system in different ways. Partial Monitor Mode ...

    Inspection and Verification
    1. Verify the customer concern is with the evaporative emission (EVAP) system. 2. Visually inspect for the following obvious signs of mechanical damage. Visual Inspection Chart Mechanical Fuel filler cap EVAP test port ...

    Security Access - Procedure
    Special Tool(s) Worldwide 418-F224, New Generation STAR (NGS) Tester 418-F052, or equivalent diagnostic tool NOTE: The security access procedure is utilized to obtain passive anti-theft system (PATS) security access. PATS security acce ...