When changing connectors match the positions from old to new or better yet test for function and be sure the connector is wired to the standard code.

Also notice that the center (A) terminal is not the brake terminal nor the ground terminal. The center terminal is listed as an auxiliary terminal and is used for either backup lights or a 12 volt (+) wire.

I recommend that this terminal be wired for 12 volt (+) for charging the breakaway switch battery. Breakaway switches are now pretty much required on most trailers with electric brakes and a charged battery is required for proper operation.

If you are trying to wire a car/truck that has separate turn and brake lights to a trailer where they are one piece you are going to need an Converter. These use diodes to change the currents to the tail lights. They look like this (CONVERTER) and are sold at most parts stores for around 10-20 bucks