Ford 2003 Mustang Workshop Manual page 3081

Is the voltage greater than 10 volts?
G5 CHECK CIRCUIT 249 (DB/LG) FOR OPEN
Check the resistance on circuit 249 (DB/LG) between C238-
3 and C2066.
Is resistance less than 10,000 ohms?
G6 CHECK THE BLOWER MOTOR GROUND
Key in OFF position.
Measure the resistance between the jumper C238-3, circuit
261 (OG/BK), and ground.
Is the resistance less than 5 ohms?
G7 CHECK CIRCUIT 261 (OG/BK) FOR AN OPEN CIRCUIT
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 circuit 249
(DB/LG) for an open. TEST
the system for normal
operation.
No
GO to G6 .
Yes
GO to G7 .
No
GO to G10 .
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.