PINPOINT TEST B: INSUFFICIENT, ERRATIC, OR NO HEAT
Vacuum Control Motor
Check the vacuum control motor for leaks with a vacuum pump.
Does the vacuum control motor hold a vacuum?
Yes
GO to A20.
No
REPLACE the vacuum control motor. TEST the system for normal operation.
A20 CHECK THE VACUUM CONTROL MOTOR INSTALLATION
Check the attachment of the vacuum control motor arm to the damper door.
Is the vacuum control motor arm attached to the door or door crank arm?
Yes
REPAIR or REPLACE the damper door. TEST the system for normal operation.
No
CONNECT the vacuum control motor arm to the door and/or crank arm and check operation. TEST the system for
normal operation.
CONDITIONS DETAILS/RESULTS/ACTIONS
B1 CHECK FOR PROPER ENGINE COOLANT LEVEL
Check the engine coolant level when hot and cold.
Is the engine coolant at the proper level (hot/cold) as indicated on the engine coolant recovery
reservoir?
Yes
GO to B2.
No
GO to B3.
B2 CHECK FOR HOT WATER TO THE HEATER CORE INLET HOSE
WARNING: The heater core inlet hose will become too hot to handle and may cause serious burns if the system is working correctly.
NOTE: Be sure that the inlet hose flow restrictor is in place and is undamaged.
Allow the engine to reach normal operating temperature.
Page 10 of 301999 F-150/250 Workshop Manual
8/16/2010http://www.fordtechservice.dealerconnection.com/pubs/con...
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