Ford Mustang Quiz
Climate Control System

Symptom Chart

In this manual: Climate Control System
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
~2min read

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 .

Test yourself

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