F 150 4WD V8-4.6L VIN 8 (2010)
For the 7-pin connector, GO to Z9.
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Z9 CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (RH STOP/TURN 7-PIN)
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Disconnect: Trailer Tow C439a.
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While applying the brake pedal, measure the voltage between the trailer tow C439a-4, circuit CAT09 (GN), harness side and ground.
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Is the voltage greater than 10 volts?
Yes
INSTALL a new trailer tow connector. TEST the system for normal operation.
No
GO to Z10.
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Z10 CHECK THE TRAILER TOW RH STOP/TURN RELAY
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Disconnect: Trailer Tow RH Stop/Turn Relay.
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Substitute a known good relay.
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For the 4-pin connector, while applying the brake pedal, measure the voltage between the trailer tow C439b-1, circuit CAT09 (GN), harness side
and ground.
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For the 7-pin connector, while applying the brake pedal, measure the voltage between the trailer tow C439a-4, circuit CAT09 (GN), harness side
and ground.
-
Is the voltage greater than 10 volts?
Yes
REMOVE the known good relay. INSTALL a new trailer tow turn relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to Z11.
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Z11 CHECK FOR VOLTAGE TO THE RH STOP/TURN LAMP RELAY COIL
