Trailer Wiring Information:

The following diagram conforms to the standard agreed upon by vehicle manufacturers and companies producing the trailer connectors.  This will allow you to hook up your old trailer to a new truck, or bring home a new commercially built trailer without any wiring hassles. The 7-blade connectors are the most widely used, and even if you donít need it now Ė you will save yourself the hassle of upgrading at a later date when you buy the next bigger and better trailer.  (Backup lights can be hooked up to 7. Auxiliary Yellow).

 THIS VIEW IS LOOKING AT THE TOW VEHICLE RECEPTACLE ON THE SCREW TERMINAL SIDE (the inside of the socket where the wires attach). 

(This is also the view of the exterior trailer connector pins)

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THIS VIEW IS LOOKING AT THE TRAILER CONNECTOR PLUG ON THE SCREW TERMINAL SIDE (The inside of the plug where the wires attach). 

(This is also the view of the pins when looking inside the cover of the tow vehicle receptacle)

  

 

The following chart should be used as a general guide only, you should always test before connecting your wiring.

This chart also may not be accurate for vehicles with factory installed trailer harnesses. In past 2-3 years manufacturers have begun to match the wire colors to the code for the common 7 way RV connector. More on that after the chart.

Caution if your vehicle has a diagnostic indicator that tells you when a lamp is burned out or not functioning, you may need special wiring adapters and testers. Not using these adapters may cause damage to the vehicle wiring or computer.
function GM Ford Chrysler
left turn & brake lights yellow lt green w/orange stripe dk green
right turn & brake lights dk green orange w/blue stripe brown
tail lights brown brown black or black w/yellow stripe
back up lights lt green black w/pink stripe violet
ground - see note 1 black black or grey black
In addition to the above some cars and trucks have a separate light for the brake light, most commonly identified by amber turn lenses in the rear. Chrysler and Jeep may have the separate light and use red lenses. If you have this type of wiring a converter is required.
brake light lt blue or pink red w/green stripe white
Note 1: We recommend attaching the trailer harness ground directly to the frame or a solidly attached sheet metal part, using a screw or bolt. The single most common cause of trailer lighting problems is a poor ground on the tow vehicle or trailer.
Notes about GM OEM wiring harness. Most GM vehicles except '99 & 2000 Silverado's match the following.

GM trailer wiring code

white ground
yellow left/brake
green right/brake
brown tail
light green backup
blue trailer brakes
red * 12 volt +
* Pickups only: since approximately 1996 the 12 volt + wire is orange. The orange and blue wires are in a separate bundle taped to the wire harness that runs down the frame on the drivers side. A white wire may also be found in that bundle, it is a brake light wire which is not normally used for trailer wiring.

Dodge tow vehicles with the Factory Tow Package Brake Connector Dodge vehicles with this package are equipped with a 15 amp fused power line which is insufficient for 3 & 4 axle (6 or 8 brake) applications. For 3 & 4 axle (6 or 8 brake) applications a separate power wire should be installed directly from the battery positive to the brake control and should include an inline 30 amp auto reset circuit breaker.

Ford tow vehicles with the Factory Tow Package Brake Connector Ford vehicles with this package are equipped with a 20 amp fused power line which is insufficient for 3 & 4 axle (6 or 8 brake) applications. For 3 & 4 axle (6 or 8 brake) applications a separate power wire should be installed directly from the battery positive to the brake control and should include an inline 30 amp auto reset circuit breaker.