1999 F-150/250 Workshop Manual
A15 CHECK THE VACUUM HARNESS
A16 CHECK THE A/C VACUUM CIRCUIT
A17 CHECK THE VACUUM CIRCUIT CONNECTIONS
A18 CHECK THE VACUUM HOSE
A19 CHECK THE VACUUM CONTROL MOTOR
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No
GO to A15.
Compare the vacuum hose color in each vacuum harness to the vacuum schematic.
Does the hose color agree with the schematics?
Yes
GO to A16.
No
REPLACE the vacuum harness. TEST the system for normal operation.
Check the A/C vacuum circuit for a pinched or kinked vacuum hose.
Is the hose pinched or kinked?
Yes
REPAIR or REPLACE the vacuum hose. TEST the system for normal operation.
No
GO to A17.
Check each vacuum hose connection to determine if it is partially connected or disconnected.
Is a vacuum hose disconnected or partially connected?
Yes
RECONNECT the hose. TEST the system for normal operation.
No
GO to A18.
Disconnect the suspect hose.
Plug one end of the hose and attach a vacuum pump to the other end. Apply vacuum and observe the gauge
reading.
Does the vacuum hose leak?
Yes
REPAIR or REPLACE the hose. TEST the system for normal operation.
No
GO to A19.
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8/16/2010