ISO 7398:1990

Overview - ISO 7398:1990 (Motorcycles - Direct current flasher units)

ISO 7398:1990 specifies the electrical characteristics and type‑test requirements for direct‑current (d.c.) flasher units intended for motorcycles with 6 V or 12 V electrical systems. The standard sets performance, marking and test procedures to verify correct operation as direction indicators, hazard warning devices, or combined units. It replaces the 1984 edition and is part of a family of motorcycle/moped flasher standards.

Key topics and technical requirements

• Scope and identification
  • Applies to d.c. flasher units for motorcycles (as defined in ISO 3833).
  • Units must be clearly marked with manufacturer name/mark, rated voltage and terminal identifications.
• Working and test voltages
  • Tests are performed at representative voltages (for example, stabilized supplies at ~6.5 V or ~13 V and adjusted filament lamp voltages around 6.75 V / 13.5 V as described in test procedures).
• Functional tests
  • Operation modes: direction indicator only, hazard warning only, or combined.
  • Starting requirements: first current “on” must begin within specified seconds after power-on; first “on”-time must be at least 0.2 s.
  • Flash-rate and “on”-time are measured after consecutive cycles and must meet the standard’s specified ranges for both direction and hazard functions.
  • Tell‑tale (indicator) behaviour: must operate in phase or counterphase with main lamps and indicate filament lamp failure by ceasing or changing frequency.
• Electrical performance
  • Maximum allowable voltage drop between input and output when operating: specified minima (e.g., not less than ~0.4 V for direction indication, ~0.5 V for hazard operation).
  • Dielectric strength: withstand 1000 V r.m.s. between terminals and exterior metallic parts for 1 minute (45–75% RH).
  • Overload strength: withstand specified high current (example test uses 35 A) for short durations.
• Environmental and mechanical tests
  • Vibration endurance (20–200 Hz, acceleration amplitude specified) and impact tests.
  • Thermal cycling and resistance: tests at +40 °C (high humidity), +80 °C and −40 °C durations specified.
  • Endurance: long‑term cycling (e.g., 100 h of 15 s on/15 s off) and continuous operation tests.
• Type‑test sampling
  • Typical sample size and test sequencing are defined (standard provides a 20‑sample basis and test allocation).

Applications and users

ISO 7398 is used by:

• Motorcycle component manufacturers designing or certifying d.c. flasher units
• OEMs (vehicle manufacturers) specifying compliant signal units for 6 V / 12 V systems
• Test laboratories performing type‑approval and conformity assessments
• Regulatory bodies and suppliers ensuring lamp/tell‑tale compatibility and vehicle safety

Related standards

• ISO 3833 (road vehicle terminology)
• ISO 7399 (Motorcycles - Alternating current flasher units)
• ISO 7400, ISO 8052 (moped flasher unit standards)

Keywords: ISO 7398, direct current flasher units, motorcycle flasher, d.c. flasher, 6 V 12 V, flash‑rate, type testing, tell‑tale, dielectric strength, endurance testing.