F 150 4WD V8-4.6L VIN 8 (2010)
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Pinpoint Tests
Pinpoint Test Z: The LH or RH Individual Trailer Turn/Stoplamp Is Inoperative
Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information. See: Diagrams/Electrical Diagrams/Diagrams By
Number
Normal Operation
The Battery Junction Box (BJB) fuse 45 (20A) supplies voltage to both trailer tow turn relays.
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.
This pinpoint test is intended to diagnose the following:
-
Fuse
-
Wiring, terminals or connectors
-
Trailer tow turn relay
-
Trailer tow connector
-
Trailer
PINPOINT TEST Z: THE LH OR RH INDIVIDUAL TRAILER TURN/STOPLAMP IS INOPERATIVE
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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Z1 VERIFY THE TRAILER LAMP OPERATION
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Ignition OFF.
-
Determine if both trailer stop/turn lamps are inoperative.
-
Are both trailer stop/turn lamps inoperative?
Yes
VERIFY the BJB fuse 45 (20A) is OK. If OK, REPAIR circuit SBB45 (GY/RD) for an open. TEST the system for normal operation.
No
For an inoperative LH trailer lamp, GO to Z2.
For an inoperative RH trailer lamp, GO to Z8.
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Z2 CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR (LH TRAILER STOP/TURN LAMP)
-
For the 4-pin connector, while applying the brake pedal, measure the voltage between the trailer tow C439b-2, circuit CAT06 (YE), harness side
and ground.