F 150 4WD V8-4.6L VIN 8 (2010)
REPAIR circuit CAT16 (GY/BN) for an open. TEST the system for normal operation.
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Pinpoint Test AC: The Trailer Lamps Are On Continuously
Trailer Lamps
Pinpoint Tests
Pinpoint Test AC: The Trailer Lamps Are On Continuously
Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information. See: Diagrams/Electrical Diagrams/Diagrams By
Number
Normal Operation - Trailer Tow Turn/Stoplamp
The trailer tow LH turn relay coil receives voltage when the vehicle LH rear stoplamp is illuminated. When the trailer tow LH turn relay is energized, the
voltage is routed to the trailer tow connector.
The trailer tow RH turn relay coil receives voltage when the vehicle RH rear stoplamp is illuminated. When the trailer tow RH turn relay is energized,
the voltage is routed to the trailer tow connector.
Trailer Tow Parking
The trailer tow parking lamp relay coil receives voltage when the vehicle parking lamps are illuminated. When the trailer tow parking lamp relay is
energized, the voltage is routed to the trailer tow connector.
This pinpoint test is intended to diagnose the following:
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Wiring, terminals or connectors
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Trailer tow relay
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Trailer
PINPOINT TEST AC: THE TRAILER LAMPS ARE ON CONTINUOUSLY
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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AC1 CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR
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Ignition ON.
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Measure the voltage between the trailer tow 4-pin connector, harness side and ground as follows: