"Check Trailer Wiring"
While returning from a week long trip from BC, we experienced our truck indicating Check Trailer Wiring on dash info centre. It then indicates trailer is connected and will go back and forth with th...
Forum Discussion
If you have a GM truck and the DIC message is exactly, CHECK TRAILER WIRING, don't bother to look at the truck. Look at the trailer wiring. The ITBC system is quite precise in determining this.
Check Trailer Wiring Message on the DIC
Some customers may experience an intermittent Check Trailer Wiring message in vehicles equipped with ITBC (Integrated Trailer Brake Controller) with no DTC stored. This message may be displayed each time the trailer's running lamps, turn signal lamps or brake lamps turn on - especially if the trailer is equipped with a large number of lamp loads.
This condition is caused by insufficient grounding between the trailer and vehicle.
To correct this condition, perform the following procedure:
Inspect and clean the ground wire (white wire) connection on the trailer side of the 7-pin connector.
Make sure that the wires inside the trailer side connector are clean and securely fastened.
If an electrical junction box exists on the trailer, make sure the wires inside the junction box are clean and securely fastened.
Once this procedure is complete, check to see if the condition has been corrected:
Remove the original trailer ground wire (white wire) from the trailer side of the 7-pin trailer connector.
Install a ring terminal (PN 12103512 or equivalent) to this wire and fasten the ring terminal to the metal or aluminum chassis of the trailer using a M6x1x20 self taping phosphate zinc coated screw (PN 11515925 or equivalent).
Pre-drill trailer chassis location with a 3/16" hole. Make sure the trailer chassis location is clean of paint or coating material prior to installation. Galvanic corrosion between dissimilar trailer and screw metals may require that this ground location be periodically cleaned.
Obtain a sufficient length of minimum 10 gauge (5.0 mm2) white wire and fasten with ring (PN 12103512 or equivalent) terminal to the trailer chassis at the same location as the original ground wire.
Install and fasten the other end of the new ground wire into the trailer side of the 7-pin trailer connector.
Install conduit on the original and new trailer ground wires, and secure the conduit to the existing trailer harness.
Check Trailer Wiring Message on the DIC
Some customers may experience an intermittent Check Trailer Wiring message in vehicles equipped with ITBC (Integrated Trailer Brake Controller) with no DTC stored. This message may be displayed each time the trailer's running lamps, turn signal lamps or brake lamps turn on - especially if the trailer is equipped with a large number of lamp loads.
This condition is caused by insufficient grounding between the trailer and vehicle.
To correct this condition, perform the following procedure:
Inspect and clean the ground wire (white wire) connection on the trailer side of the 7-pin connector.
Make sure that the wires inside the trailer side connector are clean and securely fastened.
If an electrical junction box exists on the trailer, make sure the wires inside the junction box are clean and securely fastened.
Once this procedure is complete, check to see if the condition has been corrected:
Remove the original trailer ground wire (white wire) from the trailer side of the 7-pin trailer connector.
Install a ring terminal (PN 12103512 or equivalent) to this wire and fasten the ring terminal to the metal or aluminum chassis of the trailer using a M6x1x20 self taping phosphate zinc coated screw (PN 11515925 or equivalent).
Pre-drill trailer chassis location with a 3/16" hole. Make sure the trailer chassis location is clean of paint or coating material prior to installation. Galvanic corrosion between dissimilar trailer and screw metals may require that this ground location be periodically cleaned.
Obtain a sufficient length of minimum 10 gauge (5.0 mm2) white wire and fasten with ring (PN 12103512 or equivalent) terminal to the trailer chassis at the same location as the original ground wire.
Install and fasten the other end of the new ground wire into the trailer side of the 7-pin trailer connector.
Install conduit on the original and new trailer ground wires, and secure the conduit to the existing trailer harness.
