FORD MUSTANG 2003 Workshop Manual

z
Is the voltage greater than 10 volts? G5 CHECK CIRCUIT 249 (DB/LG) FOR OPEN
z
Check the resistance on circuit 249 (DB/LG) between C238-
3 and C2066.
z Is resistance less than 10,000 ohms? Yes
REPAIR circuit 249
(DB/LG) for an open. TEST
the system for normal
operation.
No
GO to
G6 .
G6 CHECK THE BLOWER MOTOR GROUND
z
Key in OFF position.
z Measure the resistance between the jumper C238- 3, circuit
261 (OG/BK), and ground.
z Is the resistance less than 5 ohms? Yes
GO to
G7 .
No
GO to G10 .
G7 CHECK CIRCUIT 261 (OG/BK) FOR AN OPEN CIRCUIT
z
Measure the resistance between the A/C blower motor
jumper C238- 3, circuit 261 (OG/BK) and the blower motor
switch C294a- 1. Yes
REPAIR the blower motor
jumper. TEST the system
for normal operation.
No
INSTALL a new blower
motor. REFER to
Section 412 - 02 . TEST the system
for normal operation. Klj . 32 ba
412003 Mustang Workshop Manual
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z
Is the resistance more than 10,000 ohms? G8 CHECK CIRCUIT 249 (DB/LG) FOR AN OPEN CIRCUIT
z
Key in OFF position.
z Disconnect: Function Selector Switch C294c.
z Measure the resistance between C238- 3, circuit 249
(DB/LG), harness side and C294c- 4 harness side.
z Is the resistance more than 10,000 ohms? Yes
REPAIR circuit 249
(DB/LG) for an open. TEST
the system for normal
operation.
No
GO to
G9 .
G9 CHECK CIRCUIT 181 (BN/OG), FOR VOLTAGE
z
Measure the voltage between C294c- 2, circuit 181 (BN/OG),
harness side and ground.
z Is the voltage greater than 10 volts? Yes
INSTALL a new function
selector switch. REFER to
Section 412
- 04 . TEST the
system for normal
operation.
No
REPAIR circuit 181
(BN/OG) for an open. TEST
the system for normal
operation. G10 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
Yes
INSTALL a new blower
motor switch. REFER to
Section 412
- 04 . TEST the
system for normal
operation.
No
REPAIR circuit 1205 (BK).
TEST the system for
normal operation. Klj . 33 ba
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PINPOINT TEST H: THE BLOWER MOTOR OPERATES
CONTINUOUSLY IN HIGH SPEED z
Check the resistance between C294a- 3, circuit 1205 (B/K)
harness side and ground.
z Is the resistance less than 5 ohms? Test Step Result / Action to Take
H1 CHECK THE FUNCTION SELECTOR SWITCH
z
Key in ON position.
z Set the blower motor speed to low.
z Check for blower motor operation in each function
selector switch position.
z Does the blower motor operate on high in all of
the function selector positions? Yes
GO to
H2 .
No
If the blower motor operates in the
OFF position, GO to H4 .
H2 CHECK CIRCUIT 261 (OG/BK) FOR A SHORT TO
GROUND z
Key in OFF position.
z Disconnect: A/C Blower Motor C2066.
z Disconnect: Blower Motor Resistor C2185.
z Disconnect: Blower Motor Switch C294a.
z Measure the resistance between C2066 circuit 261
(OG/BK), and ground.
z Is the resistance greater than 10,000 ohms? Yes
GO to
H3 .
No
REPAIR circuit 261 (OG/BK) for a
short to ground. TEST the system
for normal operation. H3 CHECK THE BLOWER MOTOR SWITCH
OPERATION z
Measure the resistance of the blower motor switch.
Refer to the chart shown.
Blower Motor Switch Test Switch
Position Conductivity Between
Terminals Yes
INSTALL a new heater blower
motor switch resistor. REFER to
Section 412
- 04 . TEST the
system for normal operation.
No Klj . 34 ba
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PINPOINT TEST I: NO OPERATION IN HIGH BLOWER SETTING z
Is the resistance less than 5 ohms? Low None
Medium/low 2 and 3 only
Medium/high 2, 3 and 4 only
High 1, 2 and 4 only INSTALL a new heater blower
motor switch. REFER to
Section 412 - 04 . TEST the system for
normal operation. H4 CHECK THE FUNCTION SELECT SWITCH FOR A
SHORT TO BATTERY z
Key in OFF position.
z Disconnect: Function Selector Switch C294c.
z Key in ON position.
z Did the blower motor stop operating? Yes
INSTALL a new function selector
switch. REFER to
Section 412 -
04 . TEST the system for normal
operation.
No
REPAIR circuit 249 (DB/LG) for a
short to battery. TEST the system
for normal operation. Test Step Result / Action to Take
I1 CHECK CIRCUIT 261 (OG/BK) FOR AN OPEN CIRCUIT
z
Key in OFF position.
z Disconnect: Blower Motor Switch C294a.
z Key in ON position.
z Turn the function selector switch to the FLOOR position.
z Measure the voltage between blower motor switch C294a,
circuit 261 (OG/BK), harness side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
I2 .
No
REPAIR circuit 261 (OG/BK)
for an open circuit. TEST the
system for normal operation. I2 CHECK CIRCUIT 1205 (BK) FOR AN OPEN Klj . 35 ba
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PINPOINT TEST J: NO OPERATION IN LOWER SPEEDS
Component Tests z
Measure the resistance between C294a- 3, circuit 1205
(BK), harness side and ground.
z Is the resistance less than 10,000 ohms? Yes
REPAIR circuit 1205 (BK) for
an open. TEST the system for
normal operation.
No
INSTALL a new blower motor
switch. REFER to
Section 412 - 04 . TEST the system for
normal operation. Test Step Result / Action to Take
J1 CHECK CIRCUIT 261 (OG/BK) FOR AN OPEN
z
Disconnect: Blower Motor Resistor C294a.
z Key in ON position.
z Turn the function selector switch to the FLOOR position.
z Set the blower motor switch to low.
z Measure the voltage between the blower motor resistor
C2185- 4, circuit 261 (OG/BK), jumper side and ground.
z Is the voltage greater than 10 volts? Yes
GO to
J2 .
No
REPAIR circuit 261 (OG/BK) for
an open circuit between the
blower motor and the blower
motor resistor. TEST the
system for normal operation. J2 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
z
Key in OFF position.
z Measure the resistance between the blower motor
resistor C2185- 1, circuit 1205 (BK), jumper side and
ground.
z Is the resistance less than 5 ohms? Yes
INSTALL a new blower motor
resistor. REFER to
Section 412 -
03 . TEST the system for
normal operation.
No
REPAIR circuit 1205 (BK) for an
open between the blower motor
resistor and ground. TEST the
system for normal operation. Klj . 36 ba
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Heater Core
WARNING: Carbon monoxide gas is colorless, odorless and dangerous. If it is necessary
to operate the engine with the vehicle in a closed area such as a garage, always use an exhaust
collector to vent the exhaust gases outside the closed area. Failure to follow these instructions
may result in personal injury.
1. NOTE: Testing of returned heater cores reveals that a large percentage of heater cores are
good and did not require installation of a new heater core. If a heater core leak is suspected, the
heater core must be tested by following the Plugged Heater Core Component Test before the
Heater Core Pressure Test. Carry out a system inspection by checking the heater system
thoroughly as follows:
Inspect for evidence of coolant leakage at the heater water hose to heater core attachments. A
coolant leak in the heater water hose could follow the heater core tube to the heater core and
appear as a leak in the heater core.
CAUTION: Spring- type clamps are installed as original equipment. Installation and
overtightening of non- specification clamps can cause leakage at the heater water hose
connection and damage the heater core.
2. Check the integrity of the heater water hose clamps.
Heater Core— Plugged
WARNING: The heater core inlet hose will become too hot to handle if the system is
working correctly.
1. Check to see that the engine coolant is at the correct level.
2. Start the engine and turn on the heater.
3. When the engine coolant reaches operating temperature, feel the heater core outlet hose to see if it is hot.
If it is not hot:
zthe heater core may have an air pocket.
z the heater core may be plugged.
z the thermostat is not working correctly.
Heater Core— Pressure Test
Use the radiator/heater core pressure tester to carry out the pressure test. 1. NOTE: Due to space limitations, a bench test may be necessary for pressure testing.
Drain the coolant from the cooling system. For additional information, refer to Section 303 - 03A
or
Section 303 - 03B .
2. Disconnect the heater water hoses from the heater core. For additional information, refer to Klj . 37 ba
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Section 412 - 02 .
3. Install a short piece of heater water hose, approximately 101 mm (4 inches) long on each heater core tube.
4. Fill the heater core and heater water hoses with water and install Plug BT-7422- B and adapter
BT- 7422- A from the radiator/heater core pressure tester in the heater water hose ends. Secure
the heater water hoses, plug and adapter with hose clamps.
5. Attach the pump and gauge assembly from the radiator/heater core pressure tester to the adapter.
6. Close the bleed valve at the base of the gauge. Pump 241 kPa (35 psi) of air pressure into the heater core.
7. Observe the pressure gauge for a minimum of three minutes.
8. If the pressure drops, check the heater water hose connections to the core tubes for leaks. If the heater water hoses do not leak, remove the heater core from the vehicle and carry out the
bench test.
Heater Core— Bench Test
1. Remove the heater core from the vehicle. For additional information, refer to Section 412 - 02 .
2. Drain all of the coolant from the heater core.
3. Connect the 101 mm (4 inch) test heater water hoses with plug and adapter to the core tubes. Then connect the radiator/heater core pressure tester to the adapter.
4. Apply 241 kPa (35 psi) of air pressure to the heater core. Submerge the heater core in water.
5. If a leak is observed, install a new heater core. Klj . 38 ba
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A/C Evaporator/Condenser Core—
On-Vehicle Leak Test
1. Discharge and recover the refrigerant. For additional information, refer to Air Conditioning (A/C) System Recovery, Evacuation and Charging in this section.
2. NOTE: DO NOT leak test an A/C evaporator core with the suction accumulator/drier (19C836)
attached to the core tubes.
Disconnect the suspect A/C evaporator core or A/C condenser core from the A/C system. For
additional information, refer to Section 412 - 03 .
3. Clean the spring lock couplings. For additional information, refer to Spring Lock Coupling in this
section.
4. Connect the appropriate test fittings from the A/C Test Fitting Set to the evaporator or condenser tube connections.
5. NOTE: The automatic shut- off valves on some gauge set hoses do not open when connected to
the test fittings. If available, use hoses without shut- off valves. If hoses with shut-off valves are
used, make sure the valve opens when attached to the test fittings or install an adapter which
will activate the valve. The test is not valid if the shut- off valve does not open.
Connect the red and blue hoses from the manifold gauge set to the test fittings on the A/C
evaporator core or A/C condenser core. Connect the yellow hose to a known good vacuum
pump.
6. Open both gauge set valves and start the vacuum pump. Allow the vacuum pump to operate for a minimum of 45 minutes after the gauge set low pressure gauge indicates 101 kPa (30 in- Hg).
The 45- minute evacuation is necessary to remove any refrigerant from oil left in the A/C
evaporator core or A/C condenser core. If the refrigerant is not completely removed from the oil,
outgassing will degrade the vacuum and appear as a refrigerant leak.
7. If the low pressure gauge reading will not drop to 101 kPa (30 in- Hg) when the valves on the
gauge and manifold set are open and the vacuum pump is operating, close the gauge set
valves and observe the low pressure gauge. If the pressure rises rapidly to zero, a large leak is
indicated. Recheck the test fitting connections and gauge set connections before installing a
new A/C evaporator core or A/C condenser core.
8. After evacuating for 45 minutes, close the gauge set valves and stop the vacuum pump. Observe the low pressure gauge; it should remain at the 101 kPa (30 in- Hg) mark.
z If the low pressure gauge reading rises 34 or more kPa (10 or more in- Hg) of vacuum
from the 101 kPa (30 in- Hg) position in 10 minutes, a leak is indicated.
z If a very small leak is suspected, wait 30 minutes and observe the vacuum gauge.
z If a small amount of vacuum is lost, operate the vacuum pump with gauge valves open
for an additional 30 minutes to remove any remaining refrigerant from the oil in the A/C Klj . 39 ba
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evaporator core or A/C condenser core. Then recheck for loss of vacuum.
z If a very small leak is suspected, allow the system to sit overnight with vacuum applied
and check for vacuum loss.
9. If the A/C evaporator core or A/C condenser core does leak, as verified by the above procedure, install a new A/C evaporator core or A/C condenser core. For additional information, refer to
Section 412 - 03 .
A/C Compressor— External Leak Test
1. Install the A/C pressure test adapter on the rear head of the A/C compressor using the existing manifold retaining bolt.
2. Connect the high and low pressure lines of a manifold gauge set or a refrigerant recovery/recycling station such as the R- 134a A/C Service Center to the corresponding fittings
on the A/C pressure test adapter.
3. Attach the center hose of the manifold gauge set to a refrigerant container standing in an upright position.
4. Hand- rotate the compressor shaft 10 complete revolutions to distribute the oil inside the A/C
compressor.
5. Open the low pressure gauge valve, the high pressure gauge valve and the valve on the refrigerant container to allow the refrigerant vapor to flow into the A/C compressor.
6. Using the Refrigerant Leak Detector, check for leaks at the compressor shaft seal and the compressor center seal.
7. If a shaft seal leak is found, install a new shaft seal. For additional information, refer to Section 412 - 03 . If an external leak is found at the center joint of the A/C compressor, install a new A/C
compressor.
8. When the leak test is complete, recover the refrigerant. For additional information, refer to Air Conditioning (A/C) System Recovery, Evacuation and Charging in this section. Klj . 40 ba
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Klj . 41 ba
412003 Mustang Workshop Manual
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