bing tracking image
Q & A Icon

Function of Blue Wire on 7-Way Round Trailer Connector


Why do I need the blue wire on a 40 foot semi trailer? What does it control?


Expert Reply:

Sounds like you are referencing the blue wire of the 7-way round connector like what's in the attached picture. If you have no use for an additional 12 volt circuit then it would not be needed. It isn't always needed so it sounds like you may not need it at all.

click to enlarge
expert reply by:
Jameson C

Product Page this Question was Asked From

Q & A Icon

Similar Expert Q&A Pages

See More Q&A Expert Answers >>