What to do with the blue trailer brake wire when adapting from a 4 flat to a 7 blade for an RV

SOURCE: Towing wires

Here is a Utube video for you for the wire hookups! http://www.wonderhowto.com/how-to/video/how-to-install-a-trailer-wiring-harness-on-a-hyundai-sonata-164439/

SOURCE: trailer wiring

Have you checked the fuse box under the hood? There are seperate fuses for the truck lights and the trailer lights. If the fuses look good use a 12 volt test light to check for power on the turn signal pins when the brake is pushed. The brake lights and turn signals use the same wires to work. Power here would indicate the wiring and fuses on the truck is all good, meaning the trouble is on the trailer. Check the bulbs to be sure they are the correct ones, they should be dual element bulbs. Make sure you have a good ground on the trailer, usually the white wire in the 4 way plug is grounded to the trailer frame, do not depend on the trailer ball to be the ground, this is asking for trouble.

Iron

• 3018 Answers
• Posted on Nov 21, 2011

SOURCE: Trailer wiring adapter

• Here are two links to the 7 blade to 7 round pin for trailor wiring.
• http://www.easternmarine.com/7-RV-Blade-Vehicle-to-7-Round-Pin-Adapter-47595/
  
• http://www.northerntool.com/shop/tools/product_200303933_200303933
  

• Hope this helps.

SOURCE: I am trying to splice the wires for a 4 flat

Pick up a 7-to-4 adapter made especially for GMs and plug it into your existing 7-connector socket.