Is there a wiring harness for the trailer brake control to be wired into from the factory If so what are the color codes and where do I find these wires If not do i have to wire these to the plug myself. My truck is a 2003 silverado 1500

There is none from the factory. You have to splice the wires from the controller into the vehicle harness and run a wire to the trailer brake pin in the socket where the trailer cord plugs into the truck

There usually is an open harness plug under the dash. When you buy a brake controller, the instructions should come with it. The better units will have a pigtail which will plug right into the other half of the open harness plug.

If the kit you have has the pigtail connector, but loose wires needing to be connected, see if the color of the wires match those on the open connector. Then match the color of each wire.

Some years of trucks will have a heavy duty flasher to install in the Powerbox to accommodate the extra trailer lights.

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TBC means Trailer Brake Controller fault.Check for moisture/water in the trailer plug connector at the back of your truck. Water/moisture will cause TBC error codes. Look for moisture at all connections to the plug and inside the plug.Trailer brake controller that is built into your dash. If you are hooked up to a trailer it could mean you are losing your connection or ground to the trailer. If you are not connected to a trailer it means there is a problem with your brake controller possibly a short in the wiring caising the fault code. ----- It means either A) you have a bad ground on your trailer. Or B) your cable on your trailer is too short and causing it to pull out of the plug or C) you have a short in the factory trailer harness wiring or the plug is gunked up. --------- get this possibilities checked.It will help.Thanks.Helpmech.

Check this location. They have color codes and wiring diagrams. Make sure the trailer has a good ground. It MUST have the ground wire connected to the truck and trailer or you will have a floating ground through the ball. That will cause blown fuses. http://www.etrailer.com/faq-wiring.aspx

Hi. There is a grey plug with 6 wires right behind your OBDII diagnostic port on the lower dash board above your accelerator pedal.

The color of the wires on the plug are blue, green, red, white and brown. The wires are as follows:
Blue....electric trailer brake feed
Green....brake pedal switch
Red...12v postitive...always hot
White....ground
Brown....interior vehicle illumination (not used)

The factory wire harness that you will need to attach your brake controller will plug right into this plug. The factory wires are colored the same as above.

After-market and brake conroller wires are colored as follows:
Blue....electric trailer brake feed
Red.....brake pedal switch
White....ground
Black....12v positive

Sometime around 2000, GM started putting trailering pre-wire harnesses in the vehicle. Your truck may have this harness built in and would greatly simplify brake controller installation. Look under the glovebox and see if there is a wire harness tied off. There will be four wires in this harness, which should be run over to the steering column to use it. Most trailer brake controllers are compatible with this harness.
The four wires in the harness are: Red, 12vdc; black, ground; blue or purple, brake pedal; and brown or white, trailer brake wire to seven pin, four pin, or five pin connector at trailer hitch, if your truck came from the factory with a trailer hitch.
If you are adding the hitch and do not have the four wire harness, the under hood wires from your brake controller are Red, connect to one of the studs under the distribution box cover (the distribution box is on the driver's side against the firewall. Underneath the cover are two large threaded studs which are hot from the battery all the time); and the other wire from your brake controller would have to be run the length of the truck along the frame, tied off in several places, to the trailer hitch connector on the bumper. Follow the directions that came with trailer hitch wiring connector to connect this wire to the proper pin in the connector.
If this has helped you, great, and please remember to vote/comment.
Good luck!

get a cheap 12 volt test ($6 any parts store) light and have someone operate the different lights while u proble the wires, when the test light illuminates you tag that wire for what circuit was activated, brake, running, turn etc.

The trailer harness that was installed probably has a short inside the box that distributes power to the trailer pig-tail. Remove the trailer harness. You problem will be cured.

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