Hello I would like to assist you with this.
As you well know by now trailer lights and break connections can be a royal pain in the rear.
First thing I want you to do is verified with a Voltmeter that you are getting full battery voltage (12v or better) to every output wire on your connector of your vehicle when it is supposed to be there.
So check your running lights, your turn signal lights, your brake lights, and your Trailer break wire.
You should also have a ground wire in your connector.Do not count on the ground circuit being completed through the trailer hitch.
Once you have verified that you're getting all of the correct voltages to the connector at the back of the vehicle with out the trailer connected, Then please connect the trailer wire harness to the vehicle .Do not connect the trailer hitch to the vehicle. I want the trailer physically disconnected and only have the wires connected.
Now check your lights and your break function and see if this differs from before.
If nothing works then you do not have the ground connection back to the vehicle battery.
If they still work as they did before go to each light and measure the voltage and make sure it is the same voltage is that you measured at the connector on the car.
Make sure that you have a physical ground wire connecting to the trailer frame and going through the connector back to the negative side of the battery.
Most trailer wiring problems are caused by A bad ground connection.
You can test your ground connection by using a volt ohm meter with this set on oHMs. Run a wire from the nagative side of the battery to your meter and then the other probe on the meter test it to the frame of the trailer. A perfect connection would be 0 ohms. But I would say anything under 100 OHMs would be OK .
Here's a wiring diagram of how the trailer wire should be wired
If you would like any additional information or have more questions please don't hesitate to ask!
Please remember to rate my answer "Great Service" This is the only way I will get compensated for my time helping you.
IF you feel the need to click either "Helped a little" or "I expected more", please stop and reply to me via the CONTINUE CONVERSATION button with the issue you have. I will be happy to continue further and do everything I can to provide you with the service you seek.
If you are having trouble with the site or rating system please let me know as this is a new feature and some Customers have had some trouble with it.