Ford F-150 1999 Workshop Manual page 5

1999 F-150/250 Workshop Manual
A3 LEAK CHECK THE VACUUM SUPPLY HOSE
Vacuum Supply Hose
A4 CHECK THE VACUUM CHECK VALVE
A5 INSPECT THE VACUUM CHECK VALVE
A/C Vacuum Check Valve
A6 LEAK TEST THE VACUUM CHECK VALVE
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Is the hose connected?
Yes
GO to A3.
No
RECONNECT the hose. TEST the system for normal operation.
Plug one end of the hose and connect the vacuum pump to the other end. Apply vacuum and observe the gauge
reading.
Does the hose leak?
Yes
REPAIR or REPLACE the vacuum hose. TEST the system for normal operation.
No
GO to A4.
Check the A/C vacuum check valve (19A563) for correct installation by removing (one at a time) the reservoir
hose and the control assembly source hose from the A/C vacuum check valve. Check for vacuum.
Is vacuum available at both check valve ports?
Yes
GO to A6.
No
GO to A5.
Inspect the A/C vacuum check valve for an obstruction and/or proper operation. Airflow through the A/C vacuum
check valve should be in the direction toward the engine (engine connection site is marked "VAC").
Is the A/C vacuum check valve plugged or obstructed?
Yes
REPLACE the A/C vacuum check valve. TEST the system for normal operation.
No
GO to A6.
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8/16/2010