ISO 7588-1:1998

Overview

ISO 7588-1:1998 - Road vehicles - Electrical/electronic switching devices - Part 1: Relays and flashers specifies the dimensional characteristics and functional allocation of relay and flasher terminals used in road vehicles. It standardizes physical envelope sizes, tab positioning, socket aperture guidance and terminal numbering/assignment to ensure mechanical and functional interchangeability for vehicle electrical components.

Key topics and technical requirements

• Scope: Defines terminal position zones and functional allocation for relays and flashers (annex B informative).
• Tab dimensions: Tabs are specified to ISO 8092-1 size 6.3 × 0.8 mm and shall not have shoulders.
• Positioning zones: True-position tolerance zones for tab location and corresponding socket aperture locations are given (figures in the standard).
• Overall envelope: Apparatus size types A–E with maximum envelope dimensions (X, Y, Z) are defined - values are listed in Table 1 of the standard (example: Type A X max 14 mm, Z max 30 mm).
• Socket apertures: Informative annex A gives aperture guidance (entering plane and throat dimensions) pending completion of ISO work on aperture dimensions.
• Terminal functional allocation: Relay terminal numbering and functions (coil, make/break, changeover contacts) are specified; polarity note: terminal 1 plus, terminal 2 minus where polarity matters.
• Flasher allocations: Annex B provides common flasher terminal arrangements for systems with 2–5 terminals and configurations for cars with/without trailers.
• Recommendations: Female socket connectors should avoid detents to limit excessive withdrawal force.

Applications and who uses the standard

ISO 7588-1 is intended for:

• Automotive OEMs and suppliers - to design and procure relays and flasher units that fit vehicle harnesses and sockets.
• Electrical/electronic component manufacturers - for consistent terminal layouts and housings.
• Harness designers and assembly engineers - to ensure connector compatibility and correct functional wiring.
• Test labs and regulatory bodies - for verifying dimensional and functional compliance. Practical applications include turn-signal flasher units, general-purpose automotive relays, replacement components and modular electrical systems where interchangeability and reliable connections are required.

Related standards

• ISO 8092-1:1996 - Tabs for single-pole connections (dimensions and requirements).
• ISO 8092-2 - Definitions, test methods and general performance requirements (referenced).
• ISO 7588 also includes Part 2 (Electronic devices) and Part 3 (Microrelays).

Keywords: ISO 7588-1:1998, road vehicles, relays, flashers, electrical/electronic switching devices, terminals, socket apertures, terminal allocation, dimensions, ISO 8092.