I have a 2008 Ford F 150 with factory installed trailer wiring. I bought a trailer plug tester. It shows the tail light function to be dead. Brake lights, turn signals all work. Any ideas?

Hello all,

For those of you that have or occasionally borrow trailers and look at the wiring plugs with disdain (I mean face it they don't make sense, grd is white, +12vdc is black, etc), this is for you.

Plug Types/Application
7 Way - RV Trailers, Horse and Utility Trailers
6 Way - Horse, Stock and Utility
4 Way - Utility Trailers

Columns are: Color, Function, Mark on the plug.

Seven wire Trailer plugs:

Horse, stock or utility trailers:
White = Ground - 1
Blue = Electric Brakes - 2
Brown = Tail and clearance lights - 3
Black = Battery, aux power - 4
Yellow = Left turn/Brake - 5
Green = Right turn Brake - 6
Orange or Purple (not both) = Auxilliary or Reverse - 7

Recreational Vehicle:
White = Ground - 1
Blue = Electric Brakes - 2
Green = Tail and clearance lights - 3
Black = Battery, aux power - 4
Red = Left turn/Brake - 5
Brown = Right turn Brake - 6
Yellow = Auxilliary or Reverse - 7


Six wire trailer plugs:

Horse, stock or utility trailers:
White = Ground - GD
Yellow = Left turn/Brake -LT
Green = Right turn Brake -RT
Brown = Tail and clearance lights - TM
Red or Black (not both) = Battery, aux power - A
Blue = Electric Brakes - S

Recreational Vehicle: (color, use, plug mark)
White = Ground - GD
Brown = Right turn Brake - RT
Green = Tail and clearance lights -TM
Black = Battery, aux power - A
Red = Left turn/Brake - LT
Blue = Electric Brakes - S


Four wire plugs:
White = Ground
Yellow = Left turn/Brake
Green = Right turn Brake
Brown = Tail and clearance lights


Ground should be 10ga.
Others 14 ga

Best regards
Mike

Hello all,

For those of you that have or occasionally borrow trailers and look at the wiring plugs with disdain (I mean face it they don't make sense, ground is white, +12vdc is black, etc), this is for you.

This will show you how to wire trailers with seven, six and four pin connectors

Plug Types/Application
7 Way - RV Trailers, Horse and Utility Trailers
6 Way - Horse, Stock and Utility
4 Way - Utility Trailers

Columns are: Color, Function, Mark on the plug.

Seven wire Trailer plugs (Large trailers with a battery and electric brakes):

Horse, stock or utility trailers:
White = Ground - 1
Blue = Electric Brakes - 2
Brown = Tail and clearance lights - 3
Black = Battery, aux power - 4
Yellow = Left turn/Brake - 5
Green = Right turn Brake - 6
Orange or Purple (not both) = Auxilliary or Reverse - 7

Recreational Vehicle:
White = Ground - 1
Blue = Electric Brakes - 2
Green = Tail and clearance lights - 3
Black = Battery, aux power - 4
Red = Left turn/Brake - 5
Brown = Right turn Brake - 6
Yellow = Auxilliary or Reverse - 7


Six wire trailer plugs:

Horse, stock or utility trailers:
White = Ground - GD
Yellow = Left turn/Brake -LT
Green = Right turn Brake -RT
Brown = Tail and clearance lights - TM
Red or Black (not both) = Battery, aux power - A
Blue = Electric Brakes - S

Recreational Vehicle: (color, use, plug mark)
White = Ground - GD
Yellow = Not used -
Brown = Right turn Brake - RT
Green = Tail and clearance lights -TM
Black = Battery, aux power - A
Red = Left turn/Brake - LT
Blue = Electric Brakes - S


Four wire plugs:
White = Ground
Yellow = Left turn/Brake
Green = Right turn Brake
Brown = Tail and clearance lights


Ground should be 10ga.
Others 14 ga

Best regards
Mike

Hello all,

For those of you that have or occasionally borrow trailers and look at the wiring plugs with disdain (I mean face it they don't make sense, grd is white, +12vdc is black, etc), this is for you.

Plug Types/Application
7 Way - RV Trailers, Horse and Utility Trailers
6 Way - Horse, Stock and Utility
4 Way - Utility Trailers

Columns are Color, Function, Mark on the plug.

Seven wire Trailer plugs:

Horse, stock or utility trailers:
White = Ground - 1
Blue = Electric Brakes - 2
Brown = Tail and clearance lights - 3
Black = Battery, aux power - 4
Yellow = Left turn/Brake - 5
Green = Right turn Brake - 6
Orange or Purple (not both) = Auxilliary or Reverse - 7

Recreational Vehicle:
White = Ground - 1
Blue = Electric Brakes - 2
Green = Tail and clearance lights - 3
Black = Battery, aux power - 4
Red = Left turn/Brake - 5
Brown = Right turn Brake - 6
Yellow = Auxilliary or Reverse - 7


Six wire trailer plugs:

Horse, stock or utility trailers:
White = Ground - GD
Yellow = Left turn/Brake -LT
Green = Right turn Brake -RT
Brown = Tail and clearance lights - TM
Red or Black (not both) = Battery, aux power - A
Blue = Electric Brakes - S

Recreational Vehicle: (color, use, plug mark)
White = Ground - GD
Yellow = Not used -
Brown = Right turn Brake - RT
Green = Tail and clearance lights -TM
Black = Battery, aux power - A
Red = Left turn/Brake - LT
Blue = Electric Brakes - S


Four wire plugs:
White = Ground
Yellow = Left turn/Brake
Green = Right turn Brake
Brown = Tail and clearance lights


Ground should be 10ga.
Others 14 ga

Best regards
Mike