The BMPRO SwayControl is a proactive electronic stability control system designed to enhance safety when towing caravans and trailers. It automatically stabilizes the towed vehicle in the event of sway, which can be triggered by various factors such as changing road conditions, driver error, lateral winds, or passing trucks. By continuously monitoring the trailer, the SwayControl detects sway and then automatically activates the caravan/trailer brakes to bring both the towed vehicle and the tow vehicle back under control.
A key feature of the SwayControl is its asymmetric braking system. Unlike traditional symmetric sway control systems that apply both brakes equally, the SwayControl applies brakes asymmetrically. This means it can apply different braking forces to the left and right sides of the caravan/trailer, directly countering the active sway. This method allows for faster and more effective control with minimal speed reduction, distinguishing it from symmetric systems where slowing down is the primary mechanism for sway control. The system is designed to differentiate between safe maneuvering and dangerous trailer sway, eliminating the need for driver intervention during a sway event.
The SwayControl is compatible with a wide range of integrated and aftermarket brake controllers, including those from Ford, General Motors, Hayes, Nissan, Redarc, Tekonsha, Toyota, Fiat, and Chrysler. This broad compatibility ensures that many users can integrate the SwayControl into their existing towing setups.
To conserve battery power, the SwayControl incorporates a "sleep mode." After 30 minutes of inactivity, the unit automatically shuts off. It "wakes up" instantly when it receives a brake controller signal, ready to resume monitoring and controlling trailer sway. In sleep mode, the current draw from the battery is minimal, at approximately 35mA ± 2%.
Installation of the SwayControl requires suitably qualified service personnel. The unit is designed to be mounted on the underside of the caravan/trailer chassis, specifically on the first trailer frame crossmember, approximately 0.3 to 3.0 meters behind the trailer hitching point. Proper orientation is crucial for the module to function correctly; it must be mounted with the indicated "this side UP" label facing upwards, and its center (marked by an orange dot) must align with the trailer's center line. The bottom edge of the unit, indicated by an orange line on the label, must be mounted parallel to the trailer beam axle. The "trailing" edge of the crossmember is preferred for mounting, as it offers better protection from road debris. The SwayControl must be securely fastened using all four mounting holes, hard against the floor of a steel trailer, to prevent flexing or movement from wind or road vibration. Starlock washers and securely tightened screws are recommended to maintain a firm position and prevent loosening due to vibration. It is critical not to drill holes into the SwayControl unit itself, as this will void the warranty.
The SwayControl is a weather-sealed and water-resistant unit, but it is not designed to withstand direct, high-pressure spray from a power washer. Therefore, users should avoid spraying it with high-pressure water.
The wiring harness of the SwayControl consists of five wires for electrical connection and one cable for the status LED light. When connecting to the caravan/trailer's wiring harness, solder joints are the preferred termination method. If soldering is not possible, appropriate "crimp-type" weather-sealed heat-shrink connectors should be used with the manufacturer's recommended crimping tools. Shortcuts in wiring connections should be avoided, as they can increase the likelihood of electrical system failure. All connections must be durable and sealed against weather and corrosive elements to prevent loose connections that could disable the entire brake system. Using the correct wire size is also essential; incorrect wire sizes can lead to poor braking performance, brake failure, or damage to the caravan/trailer and its components, and can prevent electrical circuit protection devices from functioning properly.
The wiring connections are specific:
- The PURPLE wire connects to all left-side electric brakes.
- The PINK wire connects to all right-side electric brakes.
- The WHITE wire serves as the trailer battery/frame ground point.
- The BLUE wire receives the electric brake controller signal from the tow vehicle. It is crucial that the tow vehicle's brake controller wire (blue wire) is ONLY connected to the SwayControl's BLUE wire and NOT directly to the caravan/trailer brakes.
- The BLACK wire provides 12V DC from the tow vehicle trailer battery or BRK+ output, requiring a 30A fuse.
The caravan/trailer must be equipped with a 12V battery system of at least 50Ahr. All ground connections—caravan/trailer battery ground, SwayControl ground, and electric brake ground wires—must be securely connected to a common point on the caravan/trailer using a minimum 1.8 mm² wire. The metal chassis connection must be clean bare metal. For 12V connections, the tow vehicle's 12V charge line, the 12V caravan/trailer battery terminal, and the SwayControl's 12V (black wire) must be securely connected together with a minimum 1.8 mm² wire. The "hot" wire from the breakaway switch must connect to the +12V terminal of the caravan/trailer battery. All battery positive connections must be fused with separate 30A inline fuses. It is critical to remove any old brake wires and only use the new wires from the SwayControl, as failure to do so may prevent the system from working as intended.
After wiring, a final check is necessary:
- Ensure only PURPLE and WHITE wires from the SwayControl are connected to the left-side caravan/trailer brakes, wired in parallel.
- Ensure only PINK and WHITE wires from the SwayControl are connected to the right-side caravan/trailer brakes, wired in parallel.
- Confirm all old brake wiring has been removed.
The SwayControl unit should only be activated through a brake controller or a similar PWM device; direct voltage should not be applied. If a BMPRO TrailSafe is fitted, its activation pin should not be used to wake or test the SwayControl.
The operational status of the SwayControl is indicated by an LED Status Light. This module should be routed to the front of the caravan/trailer and mounted on a flat surface on the drawbar using self-tapping screws, in a location easily visible from the front of the caravan/trailer.
The SwayControl performs self-diagnostics every time it "wakes up" upon receiving a signal from the brake controller. During start-up, the Status Light may flash RED and GREEN approximately six times before settling on GREEN. Once operational, the system continuously monitors for faults. If no fault is detected, the GREEN light will remain on and flicker or pulse. If a fault is detected, the Status Light will turn RED, and the fault can be diagnosed from the RED flash sequence. The RED light will continue to flash until the fault is corrected, after which the GREEN light will return.
When the caravan/trailer is stationary, the GREEN light will turn off for two seconds every 60 seconds and then turn back on, indicating normal operation. If this behavior occurs while the caravan/trailer is moving, the SwayControl should be checked by a local service center.
Servicing the SwayControl should not be attempted by the user. Dismantling, modifying, or repairing the unit will void the warranty. The unit is fully sealed and contains no serviceable parts inside. For servicing, users should consult their BMPRO dealer or visit teambmpro.com for assistance.
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