Pinpoint Test
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.
- CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR
- Ignition OFF.
- Place the headlamp switch in the parking lamps on position.
- For the 4-pin connector, measure:
Trailer Tow Ground C439 Ground Pin Circuit Measurement / Action Pin Circuit 3 CAT17 (BN) - Ground - For the 7-pin connector, measure:
Trailer Tow Connector Ground Trailer Tow Connector Ground Pin Circuit Measurement / Action Pin Circuit 6 CAT17 (BN) - Ground
Is the voltage greater than 11 volts?
- Yes: The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.
- No: For the 4-pin connector, GO to 3.
For the 7-pin connector, GO to 2 .
- CHECK FOR VOLTAGE TO THE TRAILER TOW CONNECTOR (7-PIN)
- Disconnect: Trailer Tow Connector.
- Measure:
Trailer Tow Ground C4099 Ground Pin Circuit Measurement / Action Pin Circuit 6 CAT17 (BN) - Ground
Is the voltage greater than 11 volts?
- Yes: INSTALL a new trailer tow connector. TEST the system for normal operation.
- No: GO to 3 .
- CHECK THE TRAILER TOW PARKING LAMP RELAY
- Place the headlamp switch in the off position.
- Disconnect: Trailer Tow Parking Lamp Relay.
- Substitute a known good relay.
- Place the headlamp switch in the parking lamps on position.
- For the 4-pin connector, measure:
Trailer Tow Ground C439 Ground Pin Circuit Measurement / Action Pin Circuit 3 CAT17 (BN) - Ground - For the 7-pin connector, measure:
Trailer Tow Ground C4099 Ground Pin Circuit Measurement / Action Pin Circuit 6 CAT17 (BN) - Ground
Is the voltage greater than 11 volts?
- Yes: REMOVE the known good relay. INSTALL a new trailer tow parking lamp relay.
- No: REMOVE the known good relay. GO to 4 .
- CHECK THE TRAILER TOW PARKING LAMP RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Measure:
BJB Ground Trailer Tow Parking Lamp Relay Ground Pin Circuit Measurement / Action Pin Circuit 2 circuit CBP40 (YE/GN) - Ground
Is the voltage greater than 11 volts?
- Yes: GO to 5 .
- No: REPAIR the circuit.
- Measure:
- CHECK THE TRAILER TOW PARKING LAMP RELAY BJB VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Place the headlamp switch in the off position.
- Measure:
BJB Ground Trailer Tow Parking Lamp Relay Ground Pin Circuit Measurement / Action Pin Circuit 3 SBB84 (GN/RD) - Ground
Is the voltage greater than 11 volts?
- Yes: GO to 6 .
- No: VERIFY the BJB fuse 84 (20A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the appropriate OEM WIRING DIAGRAMS to identify the cause for the circuit short.
- CHECK THE TRAILER TOW PARKING LAMP RELAY GROUND CIRCUIT FOR AN OPEN
- Measure:
BJB BJB Trailer Tow Parking Lamp Relay Trailer Tow Parking Lamp Relay Pin Circuit Measurement / Action Pin Circuit 3 SBB84 (GN/RD) 1 GD120 (BK/GN)
Is the voltage greater than 11 volts?
- Yes: REPAIR the trailer tow parking lamp relay output circuit to the trailer tow connector for an open.
- No: REPAIR the trailer tow parking lamp relay ground circuit for an open.
- Measure: