2003 FORD MUSTANG Door

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
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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
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z
At each function selector switch position, apply 51 kPa (15 in- Hg)
of vacuum and check for vacuum drop.
z Does the vacuum drop exceed 3.37 kPa (1 in- Hg) per
minute? No
RECONNECT the in-
line vacuum harness
connector. GO to
A11 .
A10 LEAK TEST THE CONTROL ASSEMBLY
z
Disconnect: Function Selector Switch Vacuum.
z Connect a vacuum pump to the function selector switch supply
port and plug the control port that indicated a leak in Step A9.
z Select the function selector switch position that indicated a leak
in Step A9 and then apply 51 kPa (15 in- Hg) of vacuum.
z Does the vacuum drop exceed 1.68 kPa (0.5 in- Hg) per
minute? Yes
INSTALL a new
function selector
switch. TEST the
system for normal
operation.
No
RECONNECT the
function selector switch
vacuum connector. GO
to
A12 .
A11 CHECK THE SUPPLY HOSE FOR OBSTRUCTIONS
z
Disconnect: Mode Selector Switch Supply Hose.
z Connect a vacuum pump to the supply hose and try to pull a
vacuum. If the vacuum pump can pull a vacuum, the hose is
plugged. If the vacuum pump pulls a partial vacuum, the hose is
restricted.
z Is the hose plugged or restricted? Yes
INSTALL a new supply
hose. TEST the system
for normal operation.
No
RECONNECT the A/C
damper door switch
supply hose. GO to
A15
.
A12 LEAK TEST THE JUMPER VACUUM HARNESS
z
Disconnect:
z Disconnect the suspect hose.
z Plug one end of the suspect hose and attach a vacuum pump to
the other end. Apply 51 kPa (15 in- Hg) of vacuum to the hose. Yes
REPAIR or INSTALL a
new vacuum jumper
harness. TEST the Klj . 11 ba
412003 Mustang Workshop Manual
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z
Does the vacuum drop? system for normal
operation.
No
REPAIR or INSTALL a
new function selector
switch. TEST the
system for normal
operation.
A13 REVIEW THE VEHICLE'S HISTORY
z
Key in OFF position.
z Review the vehicles history.
z Did the climate control system function correctly prior to
this concern? Yes
GO to
A16 .
No
GO to A14 .
A14 CHECK THE VACUUM HOSES TO DAMPER DOORS
z
Connect a vacuum pump to each hose and try to pull a vacuum.
If the vacuum pump can pull a vacuum, the hose is plugged. If
the vacuum pump pulls a partial vacuum, the hose is restricted.
z Is a hose plugged or restricted? Yes
INSTALL a new
vacuum hose. TEST
the system for normal
operation.
No
GO to
A15 .
A15 CHECK THE VACUUM HARNESS
z
Compare the vacuum hose color in each vacuum harness to the
vacuum diagram.
z Does the hose color agree with the schematics? Yes
GO to
A16 .
No
INSTALL a new
vacuum harness. TEST
the system for normal
operation. A16 CHECK A/C VACUUM CIRCUIT
z
Check the A/C vacuum circuit for pinched or kinked vacuum
hose. Yes
REPAIR or INSTALL a
new vacuum hose.
TEST the system for
normal operation.
No
GO to
A17 . Klj . 12 ba
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PINPOINT TEST B: INSUFFICIENT, ERRATIC, OR NO HEAT z
Does the vacuum control motor hold a vacuum? A20 CHECK THE VACUUM CONTROL MOTOR INSTALLATION
z
Key in OFF position.
z Check the attachment of the vacuum control motor arm to
damper door.
z Is the vacuum control motor arm attached to the door or
door crank arm? Yes
REPAIR or INSTALL a
new damper door.
TEST the system for
normal operation.
No
CONNECT the vacuum
control motor arm to
the door and check
operation. TEST the
system for normal
operation.
Test Step Result / Action to Take
B1 CHECK FOR CORRECT ENGINE COOLANT LEVEL
z
Key in OFF position.
z Check the engine coolant level when hot and cold.
z Is the engine coolant at the correct level (hot/cold) as
indicated on the engine coolant recovery reservoir? Yes
GO to
B2 .
No
GO to B3 .
B2 CHECK FOR HOT WATER TO THE HEATER CORE INLET
HOSE WARNING: The heater core inlet hose will become
too hot to handle and may cause serious burns if the
system is working correctly.
z Key in START position.
z Allow the engine to reach normal operating temperature.
z Feel the heater core inlet hose. Yes
GO to
B4 .
No
TEST the engine cooling
system for correct
operation. REFER to
Section 303 - 03A or
Section 303 - 03B . Klj . 14 ba
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PINPOINT TEST F: NO OPERATION IN ALL TEMPERATURE
SETTINGS
PINPOINT TEST G: THE BLOWER MOTOR DOES NOT
OPERATE/DOES NOT OPERATE CORRECTLY INSTALL a new A/C
compressor due to low
performance. REFER to
Section 412
- 03 . TEST the
system for normal operation. Test Step Result / Action to Take
F1 CHECK THE TEMPERATURE CONTROL
z
Start the engine and run at idle. Allow the engine to reach
normal operating temperature.
z Place the function selector switch in the NORMAL A/C
position.
z Adjust the temperature control to full warm position, and
physically feel the discharge air temperature at the at the
center panel vents.
z Rotate the temperature control to full cold position, and
physically feel the discharge air temperature at the center
panel vents.
z Does the discharge air temperature vary? Yes
The temperature blend
door is functioning
correctly. RETURN to the
symptom chart.
No
GO to
F2 .
F2 CHECK FOR A BROKEN A/C TEMPERATURE CONTROL
CABLE z
Remove the climate control assembly to gain access to the
control cable head.
z Move the temperature control from full warm to full cold.
z Inspect the cable control head as you move the temperature
control.
z Does the alignment mark on the control head move? Yes
INSTALL a new
evaporator housing.
REFER to
Section 412 -
02 .
No
INSTALL a new
temperature control cable
assembly. REFER to
Section 412 - 04 .
Test Step Result / Action to Take
G1 CHECK FOR VOLTAGE AT C238
z
Disconnect: Blower Motor Jumper C238.
z Key in ON position.
z Turn the blower motor selector to LOW.
z Turn the function selector to FLOOR.
z Check for voltage between C238- 6, circuit 249 (DB/LG) and
C238- 3, circuit 261 (OG/BK). Yes
GO to
G2 .
No
GO to G4 . Klj . 30 ba
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DESCRIPTION AND OPERATION
Air Distribution
NOTE:
The air distribution system of this vehicle cannot be equipped with a cabin air filter.
There are two sources of air available to the air distribution system:
zoutside air
z recirculated air
Recirculated air is only used during MAX A/C.
Air distribution within the vehicle is determined by the function selector switch position. Airflow control
doors are used to direct airflow within the air plenum chamber. Vacuum control motors (18A318) are
used to position these airflow control doors. Refer to Section 412 - 00 for a description and operation of
each of the system functions.
The air distribution system is designed to provide airflow from the defrost nozzle when no vacuum is
applied to any of the vacuum control motors. This is done to prevent a situation where defrost cannot
be obtained due to a system vacuum leak.
Air enters the passenger compartment from the:
zinstrument panel A/C register (19893).
z heater outlet floor duct (18C433).
z windshield defroster hose nozzle (18490).
z side window demisters.
Passenger compartment air is exhausted from the vehicle through open windows or body air vents.
Instrument Panel Registers
There are A/C registers on the left and right sides of the instrument panel and in the center instrument
panel finish panel.
The LH and RH A/C registers are only serviceable as assemblies.
The center A/C registers are not serviceable as assemblies. The registers are installed with the
instrument panel center finish panel assembly. Component Locations SECTION 412-
01: Air Distribution and Filtering 2003 Mustang Workshop Manual Klj . 1 ba
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REMOVAL AND INSTALLATION
Door —
Air Inlet Duct
Removal 1. Remove the evaporator core housing. For additional information, refer to Section 412 - 02 .
2. Disconnect the vacuum line.
3. Remove the screws and remove the duct.
Installation 1. To install, reverse the removal procedure.
SECTION 412-
01: Air Distribution and Filtering 2003 Mustang Workshop Manual Klj . 1 ba
22003 Mustang Workshop Manual
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