heater FORD MUSTANG 2003 Repair Manual

REMOVAL AND INSTALLATION
Intake Manifold Runner Control (IMRC) Actuator —
3.8L
Removal and Installation 1. Disconnect the battery ground cable. For additional information, refer to Section 414 - 01 .
2. Drain the cooling system. For additional information, refer to Section 303 - 03A .
3. Remove the upper intake manifold. For additional information, refer to Section 303 - 01A .
4. Remove the fuel injector supply manifold. For additional information, refer to Section 303 - 04A .
5. Remove the coolant bypass tube. For additional information, refer to Section 303 - 03A .
6. Remove the bolt and heater water inlet tube at the back of the lower intake.
7. Remove the two stud bolts and one bolt. Position the actuator aside.
8. Disconnect the linkage and remove the actuator.
SECTION 303-
14: Electronic Engine Controls 2003 Mustang Workshop Manual Klj . 1 ba
22003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

9.
NOTE: New plastic IMRC retainers must be installed any time an IMRC rod is removed.
NOTE: Before installing the IMRC actuator, be sure to rotate the motor driver plate until the
levers make contact with the set screws, then rotate the motor until the motor bracket bolt holes
line up with the tapped holes in the lower intake manifold.
NOTE: Discard O- ring and install a new O- ring on the heater inlet tube. Lubricate the O- ring
with engine coolant prior to installation.
To install, reverse the removal procedure. Klj . 2 ba
22003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_4464/S3B~us~en~ ...

DESCRIPTION AND OPERATION
Transmission Electronic Control System
The powertrain control module (PCM) and its input/output network control the following transmission
operations:
zShift timing
z Line pressure (shift feel)
z Torque converter clutch
The transmission control is separate from the engine control strategy in the PCM, although some of
the input signals are shared. When determining the best operating strategy for transmission operation,
the PCM uses input information from certain engine- related and driver-demand related sensors and
switches.
In addition, the PCM receives input signals from certain transmission- related sensors and switches.
The PCM also uses these signals when determining transmission operating strategy.
Using all of these input signals, the PCM can determine when the time and conditions are right for a
shift, or when to apply or release the torque converter clutch (TCC). It will also determine the best line
pressure needed to optimize shift feel. To accomplish this, the PCM uses hydraulic solenoids to control
transmission operation.
The following provides a brief description of each of the sensors and actuators used to control
transmission operation.
Powertrain Control Module (PCM)
The operation of the transmission is controlled by the powertrain control module (PCM). Many input
sensors provide information to the PCM. The PCM then controls actuators which determine
transmission operation.
Air Conditioning (A/C) Clutch
An electromagnetic clutch is energized when the clutch cycling pressure switch closes. The switch is
located on the suction accumulator/drier. The closing of the switch completes the circuit to the clutch
and draws it into engagement with the compressor driveshaft. When the A/C clutch is engaged,
electronic pressure control (EPC) is adjusted by the PCM to compensate for additional load on the
engine.
Brake Pedal Position (BPP) Switch
The brake pedal position (BPP) switch tells the PCM when the brakes are applied. The torque
converter clutch disengages when the brakes are applied. The BPP switch closes when the brakes are
applied and opens when they are released.
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature (ECT) sensor detects temperature of engine coolant and supplies the
information to the powertrain control module. The ECT sensor is used to control torque converter
clutch (TCC) operation. The ECT is installed in the heater outlet fitting or cooling passage on the
engine. For engine control applications, the ECT signal is used to modify ignition timing, EGR flow and
air- to-fuel ratio as a function of engine coolant temperature.
SECTION 307-
01: Automatic Transaxle/Transmission 2003 Mustang Workshop Manual Klj . 1 ba
42003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2748/S3B~us~en~ ...

z
Refrigerant R- 134a must not be mixed with air for leak testing or used with air for any
other purpose above atmospheric pressure. R- 134a is combustible when mixed with high
concentrations of air and higher pressures.
z A number of manufacturers are producing alternative refrigerant products that are
designed to be used instead of R- 134a refrigerant. The use of any unauthorized
substitute refrigerant can severely damage the A/C components. If repair is required, use
only new or recycled refrigerant R- 134a.
CAUTION: To avoid contamination of the A/C system, always observe the following:
z Keep service tools and the work area clean.
z Never open or loosen a connection before discharging the system.
z When loosening a connection, if any residual pressure is evident, allow it to leak out
before opening the fitting.
z Evacuate a system that has been opened to install a new component or one that has
been discharged through leakage before charging.
z Seal an open fitting with a cap or plug immediately after disconnecting a component
from the system.
z Clean the outside of the fittings thoroughly before disconnecting a component from the
system.
z Do not remove the sealing caps from a new component until ready to install.
z Refrigerant oil will absorb moisture from the atmosphere if left uncapped. Do not open
an oil container until ready to use, and install the cap immediately after using. Store the
oil in a clean, moisture- free container.
z Install a new O- ring seal before connecting an open fitting. Coat the fitting and the O- ring
seal with refrigerant oil before connecting.
z When installing a refrigerant line, avoid sharp bends. Position the line away from the
exhaust or any sharp edges that can chafe the line.
z Do not open a refrigerant system or uncap a new component unless it is as close as
possible to room temperature. This will prevent condensation from forming inside a
component that is cooler than the surrounding air.
The manual climate control system heats or cools the vehicle depending on the function selector
switch position and the temperature selected.
zThe function selector switch position determines heating or cooling and air distribution.
z The temperature control setting determines the air temperature.
z The heater blower motor switch (18578) varies the blower motor speed.
Principles of Operation
There are four main principles involved with the basic theory of operation:
zheat transfer
z latent heat of vaporization
z relative humidity
z effects of pressure Heat Transfer Klj . 2 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

9 18591 Heater blower motor resistor Klj . 11 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

DIAGNOSIS AND TESTING
Climate Control System
Refer to Wiring Diagrams Cell
54 , Air Conditioner/Heater for schematic and connector information.
SECTION 412-
00: Climate Control System - General Information 2003 Mustang Workshop Manual Special Tool(s)
Connector, Refrigerant
Pressure Line
412-
093 (T94P-19623- E) Set, A/C Fittings
412-
DS028 (014- 00333, D93L-
19703- B) or equivalent Vacuum Pump Kit
416-
D002 (D95L-7559- A) or
equivalent Breakout Box, EEC-V Control
System
418- 049 (014-00950, T94L-50-
EEC- V) Worldwide Diagnostic System
(WDS)
418-
F224,
New Generation STAR (NGS)
Tester
418- F052, or equivalent
diagnostic tool Pressure Test Kit
014-
R1072 or equivalent 77 III Automotive Meter
105-
R0056 or equivalent Klj . 1 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

Item Part Number Description
1 18A318 Vacuum control motor, panel/defrost door
2 18A478 Panel/defrost door (full vacuum position)
3 — Defrost airflow
4 — Side window demister airflow
5 18B545 Temperature blend door (full heat position)
6 19860 A/C evaporator core
7 19A813 Air inlet door (full vacuum position)
8 — Outside air inlet
9 18A318 Vacuum control motor—
air inlet door 10 — Recirculated air inlet
11 19805 Blower motor
12 — Vacuum from the engine intake manifold
13 19A563 A/C vacuum check valve
14 19A566 A/C vacuum reservoir tank and bracket
15 19B888 A/C-
heater function selector switch Klj . 3 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

Function Selector Switch Vacuum Connector
V=Vacuum
NV=No Vacuum
Inspection and Verification
1. Verify the customer's concern by operating the climate control system to duplicate the condition. 16 18476 Heater core
17 18A559 Panel/floor door (full vacuum position)
18 — Floor airflow
19 18A318 Vacuum control motor—
floor/panel door 20 — Panel vent airflow
Port No. Hose Color Function
1 White Air inlet door
2 Red Panel/floor door
3 Blue Panel/floor door
4 Yellow Panel/defrost door
5 Black Vacuum source
6 — Not used
Function Selector Switch Vacuum Application Chart Switch Port Color Function Function Selector Switch Position
MAX A/C A/C Vent OFF Floor FLR/ DEF Defrost
1 White Recirc/Fresh V NV NV V NV NV NV
2 Red Floor NV NV NV V V NV NV
3 Blue Panel/floor NV NV NV V V V NV
4 Yellow Panel/defrost V V V NV NV NV NV
5 Black Vacuum source V V V V V V V Klj . 4 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

Symptom Chart
Condition
Possible Sources Action
z Incorrect/erratic direction
of airflow from outlet(s) z
No vacuum to A/C heater
function switch selector.
z A/C heater function selector
switch leaks vacuum.
z Kinked/pinched vacuum hose.
z Leaking vacuum control
motor.
z Leaking A/C vacuum check
valve.
z Leaking A/C vacuum reservoir
tank and bracket.
z Vacuum actuator arm not
connected to door crank. z
Go To Pinpoint
Test A .
z Insufficient, erratic, or no
heat z
Low engine coolant level.
z Thermostat stuck open.
z Disengaged/damaged
temperature cable. z
Go To Pinpoint
Test B .
z The A/C does not
operate/does not operate
correctly z
CASS strategy failure.
z Open fuses.
z A/C clutch relay.
z Shorted blend door actuator.
z Powertrain control module.
z Circuitry short/open.
z A/C cycling switch damaged.
z A/C system discharged/low
charge.
z Function selector switch
damaged.
z A/C pressure cut-off switch
damaged.
z A/C compressor clutch
damaged. z
Go To Pinpoint
Test C .
z The A/C is always on zCircuitry short/open.
z A/C cycling switch.
z A/C heater function selector
switch.
z Constant control relay
module.
z Incorrect A/C clutch air gap. z
Go To Pinpoint
Test D .
z Insufficient A/C cooling zRestricted A/C evaporator
core orifice.
z Low refrigerant level. z
Go To Pinpoint
Test E .
z No operation in all the
temperature settings z
Damaged blend door actuator
cable.
z Damaged air temperature
control door. z
Go To Pinpoint
Test F .
z The blower motor does
not operate z
Open fuse.
z Circuitry open/shorted.
z Damaged heater blower
motor switch (18578).
z Damaged heater blower
motor switch resistor (18591).
z Damaged blower motor relay.
z Damaged blower motor. z
Go To Pinpoint
Test G .
z The blower motor
operates continuously in z
Circuitry short/open.
z Damaged heater blower z
Go To Pinpoint Klj . 6 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

Pinpoint Tests
PINPOINT TEST P1464: DTC P1464: A/C DEMAND OUT OF SELF-
TEST RANGE high speed
motor switch resistor.
z Damaged heater blower
motor switch. Test H .
z No operation in high
blower setting z
Circuitry short/open.
z Damaged heater blower
motor switch. z
Go To Pinpoint
Test I .
z No operation in lower
speeds z
Circuitry short/open.
z Damaged heater blower
motor switch resistor.
z Damaged heater blower
motor switch. z
Go To Pinpoint
Test J .
Test Step Result / Action to Take
P14641 RECHECK FOR THE DTC
z
Key in ON position.
z Make sure the function selector switch is in the OFF
position.
z Enter the following diagnostic mode on the diagnostic
tool: PCM Self- Test.
z Is DTC P1464 retrieved? Yes
GO to
P14642 .
No
The system is functioning
correctly. This DTC will set if the
A/C is turned on when carrying
out the PCM self- test. P14642 CHECK PID ACCS WITH THE A/C CONTROL
DISCONNECTED z
Key in OFF position.
z Disconnect: Function Selector Switch C294c.
z Key in ON position.
z Enter the following diagnostic mode on the diagnostic
tool: PCM PID ACCS.
z Does PID ACCS read ON? Yes
GO to
P14643 .
No
INSTALL a new function selector
switch. REFER to Section 412 -
04 . REPEAT the PCM self-test
and verify DTC P1464 is no
longer retrieved. P14643 CHECK CIRCUIT 348 (VT) FOR A SHORT TO B+
z
Key in OFF position.
z Disconnect: PCM C175.
z Key in ON position.
z Measure the voltage at the function selector switch
C294c- 4, circuit 348 (VT), the harness side and ground. Yes
REPAIR circuit 348 (VT ) for a
short to B+. REPEAT the PCM
self-
test and verify DTC P1464 is
no longer retrieved.
No
INSTALL a new powertrain
control module. REFER to
Section 303 - 14 . REPEAT the
PCM self- test and verify DTC
P1464 is no longer retrieved. Klj . 7 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...