|Pictured below is the Pollock 7 way connector, which is the
connector style in most common use on RV trailers and is becoming
increasingly popular on horse and utility trailers. This connector
is also manufactured by the Theodore Bargman Company and there are
also some generics around. They are supposed to be interchangeable
and the wiring color code is maintained among the various brands.
As you can see in the illustration below the back side of the
connector body is labeled at each terminal. The labels are listed
below with the function assigned to that pin.
On the tow vehicle side with the exception of 96-98 Ford and
Dodge pickups and SUV's with factory installed trailer wiring, wire
color alone should not be relied on, always test and match the
function to the appropriate terminal.
On the trailer side RV's for the most part are wired to match the
connector colors. Any plug that has been changed or extended, along
with horse and utility trailers should be tested when replacing for
any reason to be sure the function matches the terminal.
It should be noted below that the center
labeled as an auxiliary circuit, most commonly used for
lights not a ground terminal as many try to make
Also after the connector diagrams find more information on wire
colors used by GM, Ford, and Dodge.