Function of Center Pin on a 7-Way RV Blade Style Trailer Connector on a 2003 Toyota 4Runner

Question:

I have a 2003 4 Runner with tow package the factory hitch connection is 7 flat. I have a coiled adaptor 7 way to 5 flat that i need to replace that has a protruding metal knob in the center. I noticed that some of your 7 way flats have this metal knob, others dont. Is this knob the ground connection or what is the difference between the adapators that do or dont have this knob? thanks

asked by: Bill K

Expert Reply:

No problem, I will be happy to help. The 7-Way you have is called a blade or RV style. The center pin will either be for reverse lights or auxiliary 12-volt power. If the trailer does not have reverse lights or does not need a second 12-volt circuit, then it would not matter if the adapter had it or not.

If the trailer has an electric reverse lockout feature, common on boat trailers with surge brakes, then you would need that center pin in the adapter and the center pole on the vehicle side connector would have to be active and connected to the reverse light circuit.

To see what function the center pole has on your vehicle side connector you will need to test it with a circuit tester such as # PTW2993. You will also need one other person to help. To test for aux power, you should just have to have the vehicle on, and that center pole should show power.

To test the reverse lights, you will need to chock the wheels, engage the emergency brake, have someone sit in the vehicle with their foot on the brake, start the vehicle, then shift into reverse. If it is connected to the reverse light circuit, then it would show power when the vehicle is in reverse.

expert reply by: Michael H