2003 FORD MUSTANG test G

z
Disconnect: CCRM C1262.
z Measure the resistance of CCRM C1262- 18, circuit 1205
(BK), harness side and ground.
z Is the resistance reading less than 5 ohms? GO to
C21 .
No
REPAIR circuit 1205 (BK) for
an open. TEST the system for
normal operation. C21 CHECK CIRCUIT 20 (WH/LB) AT THE CONSTANT
CONTROL RELAY MODULE z
Key in ON position.
z Measure the voltage at the CCRM C1262- 13, circuit 20
(WH/LB), harness side and ground.
z Is the voltage reading greater than 10 volts? Yes
GO to
C22 .
No
REPAIR circuit 20 (WH/LB) for
an open. TEST the system for
normal operation. C22 CHECK THE POWER TO THE A/C CLUTCH
z
Key in OFF position.
z Connect: CCRM 1262.
z Disconnect: A/C Clutch C100.
z Turn the function selector to the A/C position.
z Measure the voltage at the A/C clutch C100, circuit 347
(BK/YE), harness side and ground. Yes
GO to
C24 .
No
GO to C23 . Klj . 22 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

z
Is the voltage greater than 10 volts? C23 CHECK CIRCUIT 331 (PK/YE) FOR AN OPEN.
z
Key in OFF position.
z Disconnect: CCRM C1262.
z Key in ON position.
z Enter the following diagnostic mode on the diagnostic
tool:
z In the Active Command Mode command the PCM
outputs ON.
z Measure the resistance between the CCRM C1262- 22,
circuit 331 (PK/YE), harness side and ground.
z Is the resistance reading less than 5 ohms? Yes
GO to
C24 .
No
REPAIR circuit 331 (PK/YE) for
an open. TEST the system for
normal operation. C24 CHECK CIRCUIT 347 (BK/YE)
z
Key in OFF position.
z Measure the resistance between CCRM C1262- 23,
circuit 347 (BK/YE), harness side and A/C clutch C100-
1, harness side.
z Is the resistance less than 5 ohms? Yes
GO to
C25 .
No
REPAIR circuit 347 (BK/YE) for
an open. TEST the system for
normal operation. C25 CHECK CIRCUIT 347 (BK/YE) FOR A SHORT TO
GROUND. z
Measure the resistance between A/C clutch C100- 2,
circuit 1205 (BK), harness side and the CCRM C1262-
16, circuit 1205 (BK) harness side. Yes
INSTALL a new constant
control relay module. TEST the
system for normal operation. Klj . 23 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

PINPOINT TEST D: THE A/C IS ALWAYS ON z
Is the resistance less than 5 ohms? No
REPAIR circuit 1205 (BK) for
an open. TEST the system for
normal operation.
Test Step Result / Action to Take
D1 CHECK PCM PID WACF
z
Turn the function selector switch to the OFF position.
z Key in ON position.
z Enter the following diagnostic mode on the diagnostic
tool: PCM PID WACF.
z Does the PCM PID WACF read YES? Yes
REPAIR circuit 331 (PK/YE) for
a short to ground. TEST the
system for normal operation.
No
GO to
D2 .
D2 CHECK PID ACCS WITH A/C OFF
z
Enter the following diagnostic mode on the diagnostic
tool: PCM PID ACCS.
z Does the PCM PID ACCS read ON? Yes
GO to
D3 .
No
GO to D5 .
D3 CHECK FOR A FALSE INPUT SIGNAL TO THE PCM
z
Key in OFF position.
z Disconnect: PCM C175.
z Key in ON position.
z Turn the function selector switch to the OFF position.
z Measure the voltage between PCM C175- 41, circuit 198
(DG/OG) harness side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
D4 .
No
INSTALL a new powertrain
control module. REFER to
Section 303 - 14 . TEST the
system for normal operation. D4 CHECK CIRCUIT 198 (DG/OG) FOR A SHORT TO B+
z
Key in OFF position.
z Disconnect: Function Selector Switch C294c.
z Connect: PCM C175.
z Key in ON position.
z Measure the voltage at the function selector switch Yes
REPAIR circuit 348 (PK) for a
short to B+. TEST the system
for normal operation. Klj . 24 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

PINPOINT TEST E: INSUFFICIENT A/C COOLING C294c-
3, circuit 348 (PK), harness side and ground.
z Is there voltage present? No
INSTALL a new function
selector switch. REFER to
Section 412
- 04 . TEST the
system for normal operation. D5 CHECK FOR A SHORTED CLUTCH INPUT
z
Key in OFF position.
z Disconnect: A/C Clutch C100.
z Key in ON position.
z Measure for voltage at the A/C clutch C100, circuit 347
(BK/YE), harness side and ground.
z Is there voltage present? Yes
INSTALL a new constant
control relay module. TEST the
system for normal operation.
No
CHECK the clutch air gap.
REFER to
Air Conditioning (A/C) Clutch Air Gap
Adjustment .
Test Step Result / Action to Take
E1 CHECK THE CENTER A/C REGISTER DISCHARGE
TEMPERATURE z
Carry out the refrigerant system tests. Refer to
Refrigerant System Tests in this section.
z Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for center A/C register discharge
temperature.
z Is the intersection of the two lines within the upper
and lower limits? Yes
The tests indicate that the
system is functioning normally.
No
GO to
E2 . Klj . 25 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

E2 CHECK FOR NORMAL DISCHARGE PRESSURE
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for compressor discharge (high) pressure.
z Is the intersection of the two lines within the upper
and lower limits? Yes
GO to
E3 .
No
GO to E8 .
E3 EVALUATE THE SYSTEM LOW PRESSURE
PERFORMANCE z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for compressor suction (low) pressure.
z Is the intersection of the two lines within the upper
and lower limits? Yes
GO to
E4 .
No
GO to E6 .
E4 CHECK FOR A SLOW OR CONTINUOUS RUN A/C
CLUTCH CYCLE RATE z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for total A/C clutch cycle time (time ON
plus time OFF) in seconds.
z Is the intersection of the two lines above the upper
limit? Yes
GO to
E5 .
No
INSTALL a new A/C
evaporator core due to a
partially restricted or plugged
condition. REFER to Section 412 - 02 . TEST the system for
normal operation. E5 CHECK FOR A LONG OR CONTINUOUS A/C CLUTCH
OFF TIME z
Use the recorded data from the refrigerant system tests Yes Klj . 26 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

to plot a vertical line for ambient temperature and a
horizontal line for A/C clutch OFF time in seconds.
z Is the intersection of the two lines above the upper
limit? DISCHARGE and RECOVER
the system to remove
excessive moisture or
refrigerant oil. REFER to
Air Conditioning (A/C) System
Recovery, Evacuation and
Charging . TEST the system
for normal operation.
No
GO to E7 .
E6 CHECK FOR A HIGH SUCTION PRESSURE
z
Refer to the data plot used to evaluate the system low
pressure performance in Step E3.
z Is the intersection of the two lines above the upper
limit? Yes
REMOVE the A/C evaporator
core orifice to repair missing or
damaged (leaking) O-
ring
seals. REFER to Section 412 -
03 . TEST the system for
normal operation.
No
INSTALL a new A/C cycling
switch when the intersection of
the two lines is below the
lower limit. REFER to Section 412 - 03 . TEST the system for
normal operation. E7 CHECK THE AMBIENT TEMPERATURE
z
Refer to the data plot used to evaluate the system A/C
clutch OFF time in Step E5.
z Is the ambient temperature above 26°C (80°F)? Yes
This is normal operation for
the refrigerant system in high
humidity conditions.
No
DISCHARGE and RECOVER
the system to correct an
overcharge condition. REFER
to
Air Conditioning (A/C) System Recovery, Evacuation
and Charging . TEST the
system for normal operation. E8 CHECK FOR A HIGH DISCHARGE PRESSURE
z
Refer to the data plot used to evaluate the system high
pressure performance in Step E2.
z Is the intersection of the two lines above the upper
limit? Yes
GO to
E9 .
No
GO to E11 .
E9 CHECK FOR A NORMAL LOW PRESSURE
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for compressor suction (low) pressure. Yes
REFER to
Section 303 - 03A or
Section 303 - 03B . to diagnose
the engine cooling system.
TEST the system for normal
operation. Klj . 27 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

z
Is the intersection of the two lines within the upper
and lower limits? No
GO to
E10 .
E10 CHECK FOR A NORMAL TO LOW SUCTION
PRESSURE z
Refer to the data plot used to evaluate the system low
pressure performance in Step E9.
z Is the intersection of the two lines below the lower
limit? Yes
INSTALL a new A/C
evaporator core orifice due to
a partially restricted or plugged
condition. REFER to
Section 412 - 03 . TEST the system for
normal operation.
No
INSPECT the A/C condenser
core (19712) for a partially
blocked or inadequate airflow.
TEST the system for normal
operation. E11 CHECK FOR A NORMAL SUCTION PRESSURE
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for compressor suction (low) pressure.
z Is the intersection of the two lines within the upper
and lower limits? Yes
GO to
E12 .
No
GO to E15 .
E12 CHECK FOR A SLOW A/C CLUTCH CYCLE RATE
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for total A/C clutch cycle time (time ON
plus time OFF) in seconds. Yes
INSTALL a new evaporator to
compressor suction line
(19D742) due to a partially
restricted or plugged condition.
REFER to
Section 412 - 03 .
TEST the system for normal
operation.
No
GO to E13 . Klj . 28 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...

z
Is the intersection of the two lines above the upper
limit? E13 CHECK FOR A NORMAL A/C CLUTCH OFF TIME
z
Use the recorded data from the refrigerant system tests
to plot a vertical line for ambient temperature and a
horizontal line for A/C clutch OFF time in seconds.
z Is the intersection of the two lines within the upper
and lower limits? Yes
INSPECT the A/C evaporator
core due to a low or restricted
airflow. TEST the system for
normal operation.
No
GO to
E14 .
E14 CHECK FOR A LONG A/C CLUTCH OFF TIME
z
Refer to the data plot used to evaluate the system A/C
clutch OFF time performance in Step E13.
z Is the intersection of the two lines above the upper
limit? Yes
INSTALL a new A/C
condenser core due to a
partially restricted or plugged
condition. REFER to
Section 412 - 03 . TEST the system for
normal operation.
No
EVACUATE and RECHARGE
the system when the
intersection of the two lines is
below the lower limit. REFER
to Air Conditioning (A/C) System Recovery, Evacuation
and Charging . TEST the
system for normal operation. E15 CHECK FOR A MISSING A/C EVAPORATOR CORE
ORIFICE z
Remove the A/C evaporator core orifice tube. Refer to
Section 412 - 03 .
z Is the A/C evaporator core orifice missing? Yes
INSTALL a new A/C
evaporator core orifice.
REFER to
Section 412 - 03 .
TEST the system for normal
operation.
No Klj . 29 ba
412003 Mustang Workshop Manual
18. 11. 2011file:///C:/Ford/2000 - 2004/tsocache/SHEF_2308/S3B~us~en~ ...