Trailer Connector Pinouts with industry-standard colors
IF THE IMAGE IS TOO SMALL, click it.
--------------------------------------------------------------------------------
UPDATE: SAE J2863 revised the colors again, which are now below.

Instead of fighting antique wire colors & connectors, just swap to the modern USCAR standard socket, which will accept a variety of trailer sockets without any more splicing.
--------------------------------------------------------------------------------

TSB 89-14-17 Trailer Wiring Colors

Publication Date: JULY 14, 1989

LIGHT TRUCK: 1990 BRONCO, F-150, F-250, F-350

ISSUE: Trailer tow wire harness color codes have been revised to be compatible with SAE color code standards. When hooking up a vehicle to a trailer that has been wired according to the SAE standard, the wire color/circuits will match.

ACTION: Refer to the following Circuit Color Code Chart for the correct color/circuit usage.

CIRCUIT COLOR CODE CHART
CIRCUIT FUNCTION - OLD COLOR* - OLD SAE COLOR* - SAE J2863 COLOR
Trailer LH Turn/Stop - LG/O - Y - Y
Trailer RH Turn/Stop - O/LB - DG - DG
Trailer Brake Lamp From Controller - R/LG - R/LG - X
Trailer Electric Brakes Solenoid - BL/BR - DB - DB
Trailer Back Up - BK/PK - R/Y - BK/LG
Trailer Ground - W - W - W
Trailer Running/Tail - W/R - BR/W - BR/W
Trailer Power (Battery Charge) - Y - O - O
Trailer Brake Control Feed - R - R - X

Color Key - Color Abbreviations
BL or BU-Blue
BK-Black
BR-Brown
DB-Dark Blue
DG-Dark Green
GY-Gray
LB-Light Blue
LG-Light Green
O or OR-Orange
PK-Pink
P or PU-Purple
R-Red
T-Tan
V-Violet
W or WH-White
Y-Yellow
X-none specified

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: INFORMATION ONLY
--------------------------------------------------------------------------------

See also:
TSB http://www.revbase.com/BBBMotor/TSb/DownloadPdf?id=44045
Page 142 of this PDF is universal.
. . . . (WPT-421) .
_________________________________________________
7-circuit (8-post) insulated terminal block Grote Truck-Lite 50820
Dynamic 7-blade truck-side tester
4/5/6/7 trailer-side tester

Owner caption September 2010 · Photo 3286 of 5000