Ford F-150 1999 Workshop Manual page 26

1999 F-150/250 Workshop Manual
F1 CHECK THE A/C BLOWER MOTOR OPERATION
F2 CHECK THE BLOWER MOTOR SWITCH POSITIONS
F3 CHECK THE GROUND CIRCUIT
A/C Blower Motor Resistor
F4 CHECK THE CIRCUIT RESISTANCE
A/C Blower Motor Resistor
A/C Blower Motor
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Turn the function selector switch to the FLOOR position and the blower motor switch to the LO position.
Does the A/C blower motor operate properly?
Yes
GO to F5.
No
GO to F2.
Turn the function selector switch to the FLOOR position and slowly rotate the blower motor switch from the LO
position to the HI position.
Does the A/C blower motor operate in any position except HI?
Yes
GO to F4.
No
GO to F3.
Measure the resistance between A/C blower motor resistor C191-3, Circuit 57 (BK), and ground.
Is the resistance less than 5 ohms?
Yes
REPLACE the A/C blower motor resistor. RETEST the system for normal operation.
No
REPAIR Circuit 57 (BK). TEST the system for normal operation.
Measure the resistance between A/C blower motor resistor C191-2, Circuit 261 (O/BK), and the A/C blower motor
C190-1, Circuit 261 (O/BK).
Page 26 of 30
8/16/2010