The Ford Sierra is a large family car built by Ford Europe from 1982 until 1993. The following wiring diagram and electrical circuit/schematics apply for Ford Sierra Cosworth 1991 model year. Here you will find detail illustration of the electrical system circuit and wiring diagram of the Sierra. This manual covers discussion on signal and warning system including trailer lights (turn indicator, horn, hazard warning, reversing lamp, starter inhibitor switch for automatic transmission, warning lights for handbrake and brake fluid level), starting and charging system, engine management, exterior lamps, front and rear fog lamps.
Find more information about Ford Sierra Cosworth Wiring Diagram here. (source: cannell.co.uk).