2003 FORD MUSTANG vacuum

System Air Flow Description
MAX A/C
When MAX A/C is selected:
zThe air inlet door vacuum control motor is at full vacuum, closing off outside air and admitting
only recirculated air.
z The panel/defrost door vacuum control motor is at full vacuum and the panel/floor door vacuum
control motor is at no vacuum, directing airflow to the instrument panel A/C registers. A small
amount of airflow from the side window demisters will be present.
z Blended air temperature is available.
z The A/C compressor will operate if the outside temperature is above approximately 6°C (43°F).
z The blower motor is on.
NORM A/C
When NORM A/C is selected:
zThe air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment. 9 19D990 A/C evaporator core orifice
10 19860 A/C evaporator core
11 — Low pressure vapor
12 — High pressure vapor
13 — Low pressure liquid
14 — High pressure liquid Klj . 6 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

z
The panel/defrost door vacuum control motor is at full vacuum and the panel/floor door vacuum
control motor is at no vacuum, directing airflow to the instrument panel A/C registers. A small
amount of airflow from the side window demisters will be present.
z Blended air temperature is available.
z The A/C compressor will operate if the outside air temperature is above approximately 6°C (43°
F).
z The blower motor is on.
PANEL
When PANEL is selected:
zThe air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment.
z The panel/defrost door vacuum control motor is at full vacuum and the panel/floor door vacuum
control motor is at no vacuum, directing airflow to the instrument panel A/C registers. A small
amount of airflow from the side window demisters will be present.
z The temperature can be adjusted to heat the air, but the air cannot be cooled below the outside
temperature.
z The A/C compressor will not operate.
z The blower motor is on.
OFF
When OFF is selected:
zThe air inlet door vacuum control motor is at full vacuum, closing off outside air from entering
the passenger compartment.
z The panel/floor door vacuum control motor is at full vacuum and the panel/defrost door vacuum Klj . 7 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

control motor is at no vacuum, closing off airflow to the defrost duct, side window demisters,
floor duct and instrument panel A/C registers.
z The A/C compressor will not operate.
z The blower motor is off.
FLOOR
When FLOOR is selected:
zThe air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment.
z The panel/floor door vacuum control motor is at full vacuum and the panel/defrost door vacuum
control motor is at no vacuum, directing airflow to the floor duct. A small amount of airflow from
the side window demisters will be present.
z The temperature can be adjusted to heat the air, but the air cannot be cooled below the outside
temperature.
z The A/C compressor will not operate.
z The blower motor is on.
FLOOR/DEFROST
When FLOOR/DEFROST is selected:
zThe air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment.
z The panel/floor door vacuum control motor is at partial vacuum and the panel/defrost door
vacuum control motor is at no vacuum, directing airflow to the floor duct, the defroster duct, and
the side window demisters.
z The temperature can be adjusted to heat or cool the air below the outside temperature. Klj . 8 ba
112003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

z
The A/C compressor will operate if the outside air temperature is above approximately 6°C (43°
F).
z The blower motor is on.
DEFROST
When DEFROST is selected:
zThe air inlet door vacuum control motor is at no vacuum, admitting only outside air into the
passenger compartment.
z The panel/floor door and panel/defrost door vacuum control motors are at no vacuum, directing
airflow to the defroster duct and the side window demisters.
z The temperature can be adjusted to heat or cool the air below the outside temperature.
z The A/C compressor will operate if the outside air temperature is above approximately 6°C (43°
F).
z The blower motor is on. Electrical Components Klj . 9 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~ ...

Vacuum Schematic — Manual Climate Control System R-
134a Manifold Gauge Set
176- R032A or equivalent Refrigerant Leak Detector
216-
00001 or equivalent Klj . 2 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~ ...