The ESI3 was an ultra-slim, low-cost device for indication only of engine 'vital signs'. The module provided a simple alternative to traditional analogue gauges, using high-intensity LED bargraphs to indicate engine oil pressure, coolant temperature and battery voltage. Green LEDs light when parameters are within normal limits; red LEDs indicate a fault condition. The ESI3 was mounted in a front-of-panel 92 x 92mm DIN cut-out.
Production of the ESI3 was discontinued in March 2006.