Archived Trailer Guys Questions
The Trailer Boat Experts
Can you explain the pins connections between the trailer and my truck? My truck has 7 and my trailer has 5. Why can't manufacturers get on the same page and make one connection that fits both truck and trailer? I have an adaptor but the whole thing seems unnecessary. A. Maitland, Madison, WI
Answered on: 6/2005
MIKE: As RV's are becoming more popular the automotive industry (trucks) is equipping their vehicles with the connectors that can be more "universal". The 7 pin plug allows for the connection of electric brakes as well as auxiliary items, which have historically been more popular with RV's. With the popularity of electric brakes increasing in the marine industry the 7 pin connectors can also be adapted to boat trailers. The auxiliary line has found it's use for the electric trailer winches. If you do not have these options, you can buy adapters that will easily connect your 7 pin round connector on the tow vehicle to the 4 or 5 pin flat connector on the trailer. GEORGE: A 7-5 connection is now the most common and if your trailer has disc brakes, you?re probably using a 5 pole. I agree there ought to be an easier way to do this but the fact of the matter is there are adapters readily available to solve the problem.
the Trailer Boat Expert: Mike and George