Electronic horn B133E

Sound for greater safety: Signal horns are required in vehicles by law so that other road users can be clearly alerted acoustically to dangerous situations. The durable, electronic HELLA B133E horn is particularly suitable for commercial vehicles and generates maximum attention – not just acoustically, but also visually with its striking grille. Its robust housing also helps it withstand high loads.


The B133E horn is powered by a battery current pulse. This is usually transmitted by a voltage pulse controlled by the steering wheel. This voltage pulse is fed to a relay to ensure voltage dip-free control current. A magnetic field is generated in the horn by the current, which attracts the metal core or shaft, causing vibrations of the steel diaphragm.


The HELLA B133E horn is available with a low (300 Hz) and a high (450 Hz) tone, each as a 24 V variant, and produces a sound pressure level of approx. 115 dB(A) at 2 m distance. It is much more durable and problem-free than a conventional horn, as the vibration is generated electronically.

Product Advantages

  • Ideal for commercial vehicles
  • Robust housing with distinctive grille
  • Corrosion protection
  • Teflon seal to protect against humidity (optional)

Technical Data

Diameter 123 mm
Rated voltage 24 V
Sound pressure level at 2 m distance 115 dB (A) ± 3 dB (A)
Frequency range

300 Hz (low tone)

450 Hz (high tone)
Power consumption 60 W
Current consumption max. 2.5 A
Operating temperature -40 °C to +85 °C
Protection class IP 67
Lifetime 500,000 cycles (ECE-R28)
Housing material Metal
Type approval



Program Overview

Variant Part number Packaging unit
24 V, 300 Hz, low tone 3AF 005 631-227 32
24 V, 450 Hz, high tone 3AF 005 631-237 32