Ford 2003 Mustang Workshop Manual page 3080

Is the voltage greater than 10 volts?
G2 CHECK THE BLOWER MOTOR FOR VOLTAGE
Key in OFF position.
Connect: Blower Motor Jumper C238.
Disconnect: Blower Motor C2066.
Key in ON position.
Measure voltage between terminals of blower motor.
Check for voltage between circuit 249 (DB/LG) and circuit
261 (OG/BK).
Is the voltage greater than 10 volts?
G3 CHECK THE A/C BLOWER MOTOR JUMPER WIRE
Key in OFF position.
Disconnect: Blower Motor Jumper C238.
Key in ON position.
Check circuit 261 (OG/BK) for an open between C2066 and
C238-4.
Is the resistance greater than 5 ohms?
G4 CHECK CIRCUIT 249 (DB/LG)
Check for voltage between C238-6, circuit 249 (DB/LG),
harness side and ground.
Yes
INSTALL a new blower
motor. REFER to Section
412-02 . TEST the system
for normal operation.
No
GO to G3 .
Yes
REPAIR circuit 261
(OG/BK). TEST the system
for normal operation.
No
INSTALL a new blower
motor. REFER to Section
412-02 . TEST the system
for normal operation.
Yes
GO to G5 .
No
GO to G8 .