F1
CHECK THE A/C BLOWER MOTOR OPERATION
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
.
F2
CHECK THE BLOWER MOTOR SWITCH POSITIONS
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
.
F3
CHECK THE GROUND CIRCUIT
A/C Blower Motor Resistor
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.
F4
CHECK THE CIRCUIT RESISTANCE
A/C Blower Motor Resistor
A/C Blower Motor
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
1999 F-150/250 Workshop Manual
8/16/2010
http://www.fordtechservice.dealerconnection.com/pubs/con...
