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 don’t need it now – 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. | |||
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.