Left Turn and Brake Signal Does Not Work Using the Adapter 4 Pole and 7 Pole Connector # 30717  

Question:

Expert Reply:

The first thing that you will want to do is to use a circuit tester like Quickee Circuit Tester, # 3808, to test the pins for proper function at the 7-way connector, # 30717, that you just installed. I would recommend testing each pin for proper function. When looking at the 7-way connector, the drivers side brake and turn signal, or brake and left turn signal, pin should be the pin in the 9 o clock position.

If all of the pins on the 7-way connector function appropriately, then you know the issue is somewhere on the trailer. If some of the pins, or at least the pin for the left turn and brake signal does not function properly, then you know the issue is somewhere on the vehicle.

If the issue is on the vehicle, then I would recommend disconnecting the 4-way flat connector and testing the pins on your original 4-flat connector that you plugged into this adapter. If the left turn and brake signal functions properly on your original 4-flat wiring harness, then the adapter may be bad. If the left turn and brake signal does not function on your original 4-flat wiring harness, then your wiring harness may be bad. I would recommend checking that all wire connections and your ground connections are not damaged and are corrosion free.

If the issue is on your trailer, then my guess would be a poor ground connection. You should check the ground connections for your trailer connector and for each trailer light. If the ground connections look fine, then follow the wire for the left turn and brake circuit and look for any pinched, frayed or damaged sections that could be causing a short. I have attached an article on trailer wiring that you may find helpful when troubleshooting this issue.

If the issue persists or you cannot find the problem after following these steps, then let me know what you come up with and we can take further troubleshooting steps.

expert reply by: John H

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