I bought a new 7 pin pig tail from the RV trailer center. it was too short. I took it back and got a longer one. measure the length of your 4 pin pig tail. extra length is better than too short. A control for newer vehicles will plug into a port under the steering wheel, but there should be a 7 pin connector at the back of the vehicle. If there is a 4 pin outlet at the rear then you will need to get under the steering wheel area and splice into the brake peddle wiring, as I have done with a 2001 Toyota tundra. I then ran wires back to the rear. where a 4 pin factory pig tail was installed, to the tail light
plug in. I don,t know if you can get a factory 7 pin plug in. I plugged into the 4 pin, with a 7 pin 4 pin adapter. I like the use of a connector box, as Eddie suggests! You will have to buy a control unit for about $100.00. people have reviewed controllers here on the forum. My friend had a 7 pin installed, by his dealer for several hundred dollars
, it included the control unit. It is a Honda.