Ford 2003 Mustang Workshop Manual page 3083

Check the resistance between C294a-3, circuit 1205 (B/K)
harness side and ground.
Is the resistance less than 5 ohms?
PINPOINT TEST H: THE BLOWER MOTOR OPERATES
CONTINUOUSLY IN HIGH SPEED
H1 CHECK THE FUNCTION SELECTOR SWITCH
Key in ON position.
Set the blower motor speed to low.
Check for blower motor operation in each function
selector switch position.
Does the blower motor operate on high in all of
the function selector positions?
H2 CHECK CIRCUIT 261 (OG/BK) FOR A SHORT TO
GROUND
Key in OFF position.
Disconnect: A/C Blower Motor C2066.
Disconnect: Blower Motor Resistor C2185.
Disconnect: Blower Motor Switch C294a.
Measure the resistance between C2066 circuit 261
(OG/BK), and ground.
Is the resistance greater than 10,000 ohms?
H3 CHECK THE BLOWER MOTOR SWITCH
OPERATION
Measure the resistance of the blower motor switch.
Refer to the chart shown.
Blower Motor Switch Test
Switch
Position
Test Step
Conductivity Between
Terminals
Result / Action to Take
Yes
GO to H2 .
No
If the blower motor operates in the
OFF position, GO to H4
Yes
GO to H3 .
No
REPAIR circuit 261 (OG/BK) for a
short to ground. TEST the system
for normal operation.
Yes
INSTALL a new heater blower
motor switch resistor. REFER to
Section 412-04 . TEST the
system for normal operation.
No
.