Electrical wiring
Your trailer’s electrical hookup, explained simply
For your trailer’s lights, brakes and options to work, your truck and your trailer must be wired correctly. This guide explains what each plug and each pin does, how to check your truck, and what to do when something doesn’t work.
- Standard and auxiliary 7-pin plugs
- 2-pin plugs: tarp and vibrator
- Wiring sheet delivered with every trailer
The 3 kinds of plugs
7 pinsStandard plugLights, turn signals and brakes. Every trailer needs it. Black plug.
7 pinsAuxiliary plugThe extras: ABS and the trailer’s options (air lift, hook, back-up light…). It looks like the standard plug, but the wiring is different. Yellow (ISO) plug.
2 pinsTarp or vibratorA separate plug for the electric tarp or the vibrator.The standard plug, pin by pin
| Pin | Wire | Used for | In plain words |
|---|---|---|---|
| 1 | White | Ground | The return wire. If it is badly connected, nothing works or the lights act up. |
| 2 | Black | Marker lights (depending on the trailer) | The side lights. On some trailers, this pin is not used. |
| 3 | Yellow | Left turn signal | The driver-side turn signal. |
| 4 | Red | Brake | The brake lights at the rear. |
| 5 | Green | Right turn signal | The passenger-side turn signal. |
| 6 | Brown | Marker lights | The tail and marker lights. |
| 7 | Blue | Depends on the trailer | Door and suspension, air lift or ABS. See your trailer’s wiring sheet. |
The auxiliary plug
Pin 1 is always the ground. ABS is most often on pin 7. Pins 2 to 6 are for the options you control from the truck. Depending on the trailer:
- Air lift (lift axle)
- Door and suspension
- Hook release
- Back-up light
- Strobe light
- Lift gate
Common configurations by brand
Here is the standard wiring for our main brands. Pins 1, 3, 4 and 5 are the same everywhere. On an Extreme flatbed there is no auxiliary plug: the ABS is on pin 7 of the standard plug. Your wiring sheet (serial number) always takes priority, especially if your trailer has options.
| Cross Country 2- and 3-axle dump | Cobra 3-axle dump | Cobra 4-axle dump | Titan | Extreme 2- and 4-axle flatbed | Raglan 4-axle | |
|---|---|---|---|---|---|---|
| Standard pins 2 and 6 | Marker lights | Marker lights | Marker lights | Marker lights | Marker lights | Marker lights |
| Standard pin 7 | Door and suspension | Door and suspension | Air lift | Air lift | ABS | As per the sheet |
| Auxiliary pin 2 | — | — | Door and suspension | — | No auxiliary plug | — |
| Auxiliary pin 3 | — | — | — | Back-up light | No auxiliary plug | — |
| Auxiliary pin 7 | ABS | ABS | ABS | ABS | No auxiliary plug | ABS |
| 2-pin plugs | Tarp (horizontal), vibrator (vertical) | Depending on options | Depending on options | Depending on options | — | Depending on options |
The 2-pin plugs: tarp or vibrator
How to find the pins
- The biggest pin, at the top, is pin 1 (ground).
- Pin 7 is in the centre.
- The numbers are often engraved inside the plug cover.
- Pin 2 is on the driver side.
Your wiring sheet
Every Remorques Labelle trailer is delivered with its wiring sheet, prepared for its serial number. It shows what each pin of the standard and auxiliary plugs does. Keep it in your truck: it is the reference for your trailer.
Before you pick up your trailer
- Does your truck have 2 seven-pin plugs (standard and auxiliary)?Without an auxiliary plug, the options controlled from the truck will need a wire.
- Is pin 7 (blue) of your standard plug powered?Depending on the trailer, it is used for the door and suspension, the air lift or the ABS.
- Which options do you want to control from the truck?Air lift, hook, back-up light, lift gate: each one takes a pin on the auxiliary plug.
- Do you have a 2-pin plug? Horizontal or vertical?Horizontal for the tarp, vertical for the vibrator.
- For the tarp: a switch in the truck or a remote?Tell us when you order.
Checking your truck with a test light
- Key ON. Clip the test light to the truck frame (ground).
- Turn on the marker lights: the test light should light up on pins 2 and 6 of the standard plug.
- Left turn signal: pin 3. Right turn signal: pin 5. Brake pedal: pin 4.
- Pin 7 (blue) of the standard plug: check whether it is powered all the time or only with a switch in the truck.
- Auxiliary plug: press each truck switch one at a time and note which pin lights up.
- Compare with your trailer’s wiring sheet.
Something not working? Look here
| Problem | Where to look |
|---|---|
| Left turn signal not working | Standard plug, pin 3 |
| Right turn signal not working | Standard plug, pin 5 |
| No brake light | Standard plug, pin 4 |
| Marker lights off | Standard plug, pins 2 and 6 |
| Everything is dim or flashes together | Ground, pin 1 |
| ABS light stays on | Auxiliary plug pin 7, or as per your sheet |
| Door, suspension or air lift not responding | Standard plug pin 7, or auxiliary (as per your sheet) |
| Hook, lift gate or back-up light | Auxiliary plug, pins 2 to 6 (as per your sheet) |
| Tarp not working | Horizontal 2-pin plug |
| Vibrator not working | Vertical 2-pin plug |
Frequently asked questions
My truck has no auxiliary plug. Is that a problem?
The lights and brakes will work with the standard plug. The ABS can also be wired to the standard plug. However, the options you control from the truck (air lift, hook, lift gate…) will need a wire on your truck. Talk to us before delivery.
The ABS light stays on on my trailer. Why?
The ABS is probably not powered. Check the pin shown for the ABS on your wiring sheet (most often pin 7 of the auxiliary plug).
Why two different 2-pin plugs?
The shape is different so the tarp and the vibrator can’t be mixed up: horizontal for the tarp, vertical for the vibrator.
I lost my trailer’s wiring sheet.
Call us with your trailer’s serial number: we will prepare a new one for you.
Need help?
A question about your trailer’s wiring? Call us or come see us at 1400 rue de Jaffa, Laval, Quebec H7P 4K9. Our garage can also check your truck before delivery.