F 150 4WD V8-4.6L VIN 8 (2010)
If the trailer battery charge relay is always energized (or the contacts are stuck in a closed position), the trailer can drain the vehicle battery.
This pinpoint test is intended to diagnose the following:
-
Fuse
-
Wiring, terminals or connectors
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Trailer battery charge relay
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Trailer tow connector
-
Trailer
PINPOINT TEST AD: THE TRAILER BATTERY CHARGING IS INOPERATIVE/IS ALWAYS CHARGING
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the
connector.
NOTE: Before beginning diagnostics, visually inspect the trailer tow connector for signs of corrosion or damage. Repair or install a new trailer tow
connector as required.
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AD1 CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR (BATTERY CHARGE ALWAYS ON)
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Ignition OFF.
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Measure the voltage between the trailer tow connector pin 5, circuit CAT14 (OG), component side and ground.
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Is any voltage present?
Yes
GO to AD8.
No
GO to AD2.
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AD2 CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR (BATTERY CHARGE INOPERATIVE)
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Ignition ON.
-
Measure the voltage between the trailer tow connector pin 5, circuit CAT14 (OG), component side and ground.
-
Is the voltage greater than 10 volts?