F 350 2WD Pickup V8-6.9L DSL (1983)
Vacuum Pump: Testing and Inspection
A-1 Condition Isolation
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Block the wheels and apply the parking brake.
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Place the transmission in PARK or NEUTRAL.
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Key ON engine running.
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Disconnect the low-vacuum switch. Run engine at normal idle speed. Apply brakes.
^ Does brake warning light illuminate?
YES -- Condition related to the brake hydraulic system.
NO -- Condition related to the vacuum pump. Go to A2. See: A-2 Vacuum Pump Output
