[A/S] Umbilical wiring codes (1966-1981)

[Charlie/Betty Burke <cbburke@xxxxxxxxxxxxx>]

I've been asked off list to provide the wiring code for the umbilical
cord between the trailer and the tow vehicle. Over the years there have
been several different pin and plug shapes. For the period listed above
the following chart lists the wiring colors and codes and compares them
to the current flat six pin (with 1 round in the middle) commonly
referred to as a 7 pin flat plug:

Old style plugs                            Wire
color                        New plug

Ground
White                            Ground
Left turn/Stop
Red                              Left turn/Stop
Right turn/Stop
Brown                          Right turn/Stop
Tail light/Clearance
Green                            Tail light/Clearance

Back up Light
Black                           Charge Line/12V
Trailer Brake
Yellow                          Back up Light
Charge Line/12V
Blue                             Trailer Brake

Our intent here is always to make the trailer plug compatible with the
current standard wiring with a 7 pin flat plug/socket. All of the
plug/sockets we get these days have the color code cast into the back of
the plastic plug/socket body. As you can see in order to make the
trailer plug compatible there are three wires that must be interchanged.
Black will go on the center pin, the Yellow wire will go on the pin
labeled BLU, and the Blue wire goes on the pin labeled BLACK.

For those with the gray plastic Signal Stat plug/sockets that allow you
to completely remove the umbilical when not in use, the original
plug/sockets are no longer available. There is however an available
replacement. Pollack makes metal 7 pin plugs and sockets with round
pins. The plug will fit in the Signal Stat socket. However, if the
socket fails it is necessary to replace both the plug and socket as the
Signal Stat plug will not fit into the Pollack socket.
Having said that so many times, the plug is the part on the wire and the
socket is the part on either the trailer or tow vehicle.

Charlie

Ya gotta read that more than once, it confused me!