Pinpoint Tests
PINPOINT TEST A: IMPROPER/ERRATIC DIRECTION OF AIRFLOW FROM OUTLET
No operation in all the temperature settings
Temperature blend door actuator control.
Temperature blend door.
A/C electronic blend door actuator motor.
Circuitry open/shorted.
GO to Pinpoint Test D
.
The blower motor does not operate
Fuse.
Circuitry open/shorted.
A/C blower motor switch.
A/C blower motor resistor.
A/C blower motor.
GO to Pinpoint Test E
.
The blower motor does not operate properly
Circuitry short/open.
A/C blower motor resistor.
A/C blower motor switch.
GO to Pinpoint Test F
.
No operation in high blower setting
A/C blower motor resistor.
A/C blower motor switch.
GO to Pinpoint Test G
.
CONDITIONS
DETAILS/RESULTS/ACTIONS
A1
CHECK THE SYSTEM AIRFLOW
Place the heater blower motor switch in the HI position.
Check for proper airflow from each function selector switch position at engine idle and during engine speed
acceleration.
Is there airflow from defroster outlets under all conditions?
Yes
GO to
A2
.
No
If the airflow is from defroster outlets in all switch positions only under engine speed acceleration, GO to
A19
.
If the airflow is incorrect under one or more conditions, GO to
A13
.
If the airflow is correct under all conditions, RETURN to the Symptom Chart.
A2
CHECK THE VACUUM SUPPLY HOSE
Verify the vacuum supply hose is connected between the engine manifold and the A/C vacuum check valve.
Page 4 of 30
1999 F-150/250 Workshop Manual
8/16/2010
http://www.fordtechservice.dealerconnection.com/pubs/con...
