Pinpoint Test X: The Trailer Battery Charging Is Inoperative/Does Not Operate Correctly
Trailer Lamps
Pinpoint Tests
Pinpoint Test X: The Trailer Battery Charging Is Inoperative/Does Not Operate Correctly
Refer to Wiring Diagram Set 95, Trailer/Camper Adapter for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 11, Fuse and Relay Information for schematic and connector information. Diagrams By Number
Normal Operation
The trailer battery charge relay coil receives voltage from the Smart Junction Box (SJB) fuse 44 (10A) through circuit CBP44 (VT) when the ignition switch is in the RUN position. Ground for the trailer battery charge relay coil is supplied through circuit GD123 (BK/GY). The Battery Junction Box (BJB) fuse 63 (30A) supplies voltage to the trailer battery charge relay switch side. When the trailer battery charge relay is energized, the voltage is routed to the trailer tow connector through circuit CAT14 (OG).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Trailer tow connector
- Trailer battery charge relay
- Trailer
- SJB
PINPOINT TEST X: THE TRAILER BATTERY CHARGING IS INOPERATIVE/DOES NOT OPERATE CORRECTLY
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.
-------------------------------------------------
X1 CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR (BATTERY CHARGE INOPERATIVE)
- Ignition ON.
- Measure the voltage between the trailer tow connector battery charge voltage supply pin, circuit CAT14 (OG), component side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to X8.
No
GO to X2.
-------------------------------------------------
X2 CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR (BATTERY CHARGE INOPERATIVE)
- Ignition OFF.
- Disconnect: Trailer Tow C4099.
- Ignition ON.
- Measure the voltage between the trailer tow C4099-5, circuit CAT14 (OG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new trailer tow connector. TEST the system for normal operation.
No
GO to X3.
-------------------------------------------------
X3 CHECK THE TRAILER BATTERY CHARGE RELAY (INOPERATIVE)
- Ignition OFF.
- Disconnect: Trailer Battery Charge Relay.
- Substitute a known good relay.
- Ignition ON.
- Measure the voltage between the trailer tow C4099-5, circuit CAT14 (OG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
REMOVE the known good relay. INSTALL a new trailer battery charge relay. TEST the system for normal operation.
No
REMOVE the known good relay. GO to X4.
-------------------------------------------------
X4 CHECK FOR VOLTAGE TO THE TRAILER TOW BATTERY CHARGE RELAY
- Measure the voltage between the trailer battery charge relay pin 3, circuit SBB63 (WH/RD), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to X5.
No
VERIFY the BJB fuse 63 (30A) is OK. If OK, REPAIR circuit SBB63 (WH/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.
-------------------------------------------------
X5 CHECK FOR VOLTAGE TO THE TRAILER TOW BATTERY CHARGE RELAY USING THE RELAY GROUND PIN
- Ignition OFF.
- Measure the voltage between the trailer battery charge relay pin 3, circuit SBB63 (WH/RD),BJB face side and the trailer battery charge relay pin 2, circuit GD123 (BK/GY), BJB face side.
- Is the voltage greater than 10 volts?
Yes
GO to X6.
No
REPAIR circuit GD123 (BK/GY) for an open. TEST the system for normal operation.
-------------------------------------------------
X6 CHECK FOR VOLTAGE TO THE TRAILER BATTERY CHARGE RELAY COIL (INOPERATIVE CONDITION)
- Ignition ON.
- Measure the voltage between the trailer battery charge relay pin 1, circuit CBP44 (VT), BJB face side and ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit CAT14 (OG) for an open. TEST the system for normal operation.
No
VERIFY the SJB fuse 44 (10A) is OK. If OK, GO to X7. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
-------------------------------------------------
X7 CHECK THE TRAILER BATTERY CHARGE RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: SJB C2280e.
- Measure the resistance between the trailer battery charge relay pin 1, circuit CBP44 (VT), BJB face side and the SJB C2280e-8, circuit CBP44 (VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to X12.
No
REPAIR circuit CBP44 (VT) for an open. TEST the system for normal operation.
-------------------------------------------------
X8 CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR (BATTERY CHARGE ALWAYS ON)
- Ignition OFF.
- Measure the voltage between the trailer tow connector battery charge voltage supply pin, circuit CAT14 (OG), component side and ground.
- Is any voltage present?
Yes
GO to X9.
No
The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
-------------------------------------------------
X9 CHECK THE TRAILER BATTERY CHARGE VOLTAGE SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: Trailer Battery Charge Relay.
- Measure the voltage between the trailer tow connector battery charge voltage supply pin, circuit CAT14 (OG), component side and ground.
- Is any voltage present?
Yes
REPAIR circuit CAT14 (OG) for a short to voltage. TEST the system for normal operation.
No
GO to X10.
-------------------------------------------------
X10 CHECK FOR VOLTAGE TO THE TRAILER BATTERY CHARGE RELAY COIL
- Measure the voltage between the trailer battery charge relay pin 1, circuit CBP44 (VT), BJB face side and ground.
- Is any voltage present?
Yes
GO to X11.
No
INSTALL a new trailer battery charge relay. TEST the system for normal operation.
-------------------------------------------------
X11 CHECK THE TRAILER BATTERY CHARGE RELAY COIL SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: SJB C2280e.
- Measure the voltage between the trailer battery charge relay pin 1, circuit CBP44 (VT), BJB face side and ground.
- Is any voltage present?
Yes
REPAIR circuit CBP44 (VT) for a short to voltage. TEST the system for normal operation.
No
GO to X12.
-------------------------------------------------
X12 CHECK FOR CORRECT SJB OPERATION
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new SJB. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
-------------------------------------------------