Pinpoint Test Z: The Individual Trailer Lamp Is Inoperative - Trailer Stop/Turn Lamp
Trailer Lamps
Pinpoint Tests
Pinpoint Test Z: The Individual Trailer Lamp Is Inoperative - Trailer Stop/Turn Lamp
Refer to Wiring Diagram Set 95 (Escape/Mariner, Escape Hybrid/Mariner Hybrid), Trailer/Camper Adapter for schematic and connector information. Diagrams By Number
Normal Operation
The Battery Junction Box (BJB) fuse 14 (15A) supplies voltage to the LH and RH trailer tow stop/turn relays. The trailer tow stop/turn relay coils are grounded through circuit GD120 (BK/GN).
The trailer tow LH stop/turn relay coil receives voltage from circuit CLS18 (GY/BN) when the vehicle LH rear stoplamp is illuminated. When the trailer tow LH stop/turn relay is energized, voltage is routed to the trailer tow connector through circuit CAT06 (YE).
The trailer tow RH stop/turn relay coil receives voltage through circuit CLS19 (VT/OG) when the vehicle RH rear stoplamp is illuminated. When the trailer tow RH stop/turn relay is energized, voltage is routed to the trailer tow connector through circuit CAT09 (GN).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Trailer tow stop/turn relay
- Trailer
PINPOINT TEST Z: THE INDIVIDUAL TRAILER LAMP IS INOPERATIVE - TRAILER STOP/TURN LAMP
NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.
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Z1 CHECK CIRCUIT CAT06 (YE) OR CIRCUIT CAT09 (GN) FOR VOLTAGE
- Ignition OFF.
- Disconnect: Trailer Tow C439.
- For the LH trailer stop/turn lamp, while applying the brake pedal, measure the voltage between the trailer tow C439-2, circuit CAT06 (YE), harness side and ground.
- For the RH trailer stop/turn lamp, while applying the brake pedal, measure the voltage between the trailer tow C439-1, circuit CAT09 (GN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
No
GO to Z2.
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Z2 CHECK THE TRAILER TOW STOP/TURN RELAY
- Disconnect: Suspect Trailer Tow Stop/Turn Relay.
- Substitute a know good relay.
- For the LH trailer stop/turn lamp, while applying the brake pedal, measure the voltage between the trailer tow C439-2, circuit CAT06 (YE), harness side and ground.
- For the RH trailer stop/turn lamp, while applying the brake pedal, measure the voltage between the trailer tow C439-1, 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 stop/turn relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to Z3.
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Z3 CHECK CIRCUIT CLS18 (GY/BN) OR CIRCUIT CLS19 (VT/OG) FOR AN OPEN
- While applying the brake pedal, measure the voltage between the trailer tow LH stop/turn relay pin 2, circuit CLS18 (GY/BN), BJB face side and ground; or between the trailer tow RH stop/turn relay pin 2, circuit CLS19 (VT/OG), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Z4.
No
REPAIR the circuit in question for an open. TEST the system for normal operation.
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Z4 CHECK CIRCUIT SBB14 (BN/RD) FOR AN OPEN
- Measure the voltage between the trailer tow LH stop/turn relay pin 3, circuit SBB14 (BN/RD), BJB face side and ground; or between the trailer tow RH stop/turn relay pin 3, circuit SBB14 (BN/RD), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to Z5.
No
VERIFY the BJB fuse 14 (15A) is OK. If OK, REPAIR circuit SBB14 (BN/RD) for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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Z5 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the trailer tow LH turn relay pin 1, circuit GD120 (BK/GN), BJB face side and ground; or between the trailer tow RH turn relay pin 1, circuit GD120 (BK/GN), BJB face side and ground.
- Is the resistance less than 5 ohms?
Yes
REPAIR circuit CAT06 (YE) (LH trailer stop/turn) or circuit CAT09 (GN) (RH trailer stop/turn) for an open. TEST the system for normal operation.
No
REPAIR circuit GD120 (BK/GN) for an open. TEST the system for normal operation.
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