1. Introduction
The HELLA BM40-97dB(A) Electric Reverse Warning Signal is designed to enhance safety for commercial vehicles during reversing operations. This high-frequency alarm emits an audible signal when the vehicle is in reverse, alerting pedestrians and other vehicles to its presence. Its robust construction and wide voltage compatibility make it suitable for various demanding environments.
2. Safety Information
Please read and understand all safety instructions before installing or operating this product. Failure to follow these instructions may result in property damage, injury, or death.
- Professional Installation Recommended: Installation should be performed by qualified personnel to ensure correct wiring and compliance with vehicle electrical systems.
- Local Regulations: Always check and comply with local traffic laws and regulations regarding the use of reverse warning signals. In some regions, installation of an audible reverse alarm is mandatory for vehicles with limited rear visibility.
- Disconnect Power: Before any installation or maintenance, ensure the vehicle's battery is disconnected to prevent electrical shock or short circuits.
- Personal Protective Equipment (PPE): Wear appropriate PPE, such as safety glasses and gloves, during installation.
- Sound Level: This device produces a sound level of 97dB. Be aware of the loud output and avoid prolonged exposure without hearing protection in close proximity.
- Secure Mounting: Ensure the device is securely mounted to prevent detachment due to vibrations or impacts.
3. Package Contents
- 1x HELLA BM40-97dB(A) Electric Reverse Warning Signal (Model: 3SL 996 139-551)
4. Specifications
This image shows the HELLA BM40-97dB(A) Electric Reverse Warning Signal, highlighting its robust black housing and sound output grille. The integrated mounting bracket is visible at the top.
A side view of a HELLA Heavy Duty Back-Up Alarm, similar in design to the BM40-97dB(A) model, shown next to its product packaging. This illustrates the compact and durable construction.
| Feature | Detail |
|---|---|
| Model Number | 3SL 996 139-551 |
| Brand | Hella |
| Sound Level | 97 dB(A) |
| Voltage Range | 12V - 36V |
| Frequency Range | 1200 Hz |
| Dimensions (L x W x H) | 181mm x 83mm x 74mm (7.13 x 3.27 x 2.91 inches) |
| Weight | 1.2 kg (2.65 lbs) |
| Housing Material | Glass fiber reinforced nylon |
| Electronics Protection | Epoxy resin insulation (against rust, moisture, vibrations) |
| Connector Type | DEUTSCH connector |
| Cable Length | 150mm |
| Mounting | Screwed, integrated mounting bracket |
| Compliance | ECE |
5. Setup and Installation
Proper installation is crucial for the optimal performance and longevity of the reverse warning signal.
- Choose Mounting Location: Select a location at the rear of the vehicle that is protected from direct impact but allows for unobstructed sound propagation. The integrated mounting bracket facilitates secure attachment.
- Secure Mounting: Use appropriate fasteners to securely screw the warning signal into place. Ensure the mounting surface is stable and can support the device's weight and vibrations.
- Wiring Connection: The device comes with a 150mm cable and a DEUTSCH connector. Connect the warning signal to the vehicle's reverse light circuit. This ensures the alarm activates automatically when reverse gear is engaged.
- Voltage Compatibility: Verify that the vehicle's electrical system voltage (12V to 36V) is within the operating range of the warning signal.
- Test Functionality: After installation, reconnect the vehicle's battery. Engage reverse gear (with appropriate safety precautions) to confirm the alarm functions correctly and emits a clear, audible signal.
This image displays various HELLA acoustic devices, including a HELLA BM10 Back-Up Alarm and other horn types, illustrating the range of warning signals offered by the brand. The BM40-97dB(A) is part of this product family.
6. Operating Instructions
The HELLA BM40-97dB(A) Electric Reverse Warning Signal operates automatically.
- When the vehicle's reverse gear is engaged, the warning signal will automatically activate.
- It will emit a continuous, high-frequency sound at 97 dB(A) to alert individuals in the vicinity that the vehicle is moving backward.
- The alarm will cease sounding once the reverse gear is disengaged.
7. Maintenance
The HELLA BM40-97dB(A) is designed for durability and requires minimal maintenance.
- Regular Inspection: Periodically check the warning signal for any visible damage, loose connections, or corrosion.
- Cleaning: Keep the device clean from dirt, mud, and debris. Use a soft, damp cloth for cleaning. Avoid using harsh chemicals or abrasive materials.
- No User-Serviceable Parts: The internal components are sealed with epoxy resin for protection. Do not attempt to open or repair the unit, as this will void the warranty and may cause damage.
8. Troubleshooting
If you encounter issues with your reverse warning signal, refer to the following troubleshooting guide:
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound when reverse gear is engaged. | No power supply; faulty wiring; blown fuse in the reverse light circuit; faulty reverse light switch. | Check power connections and wiring for continuity. Inspect the fuse for the reverse light circuit and replace if necessary. Consult a professional mechanic to check the reverse light switch. |
| Intermittent sound or weak signal. | Loose wiring connections; corrosion at terminals; excessive vibration. | Ensure all connections are tight and free from corrosion. Clean terminals if necessary. Verify secure mounting to minimize vibration. |
| Alarm sounds continuously (not only in reverse). | Incorrect wiring; faulty reverse light switch. | Review wiring diagram and ensure correct connection to the reverse light circuit. Consult a professional mechanic to check the reverse light switch. |
If the problem persists after attempting these solutions, contact HELLA customer support or a qualified service technician.
9. Warranty and Support
HELLA products are manufactured to high-quality standards and are backed by a manufacturer's warranty. For specific warranty terms and conditions, please refer to the documentation provided with your purchase or visit the official HELLA website.
For technical support, spare parts, or service inquiries, please contact your HELLA dealer or the HELLA customer service department. Contact information can typically be found on the HELLA website or on your product packaging.
When contacting support, please have your product model number (3SL 996 139-551) and purchase date available.
