Because the gauges can work with so many different styles of inputs, you will need to tell the cluster what you have. To do this you push and hold the button, start the car, release the button, and cycle through each parameter by tapping the button, which is clearly explained in the instructions. Basically, you need to tell the tach that the motor is an 8-cylinder and calibrate the speedo in one of two fashions: 1. Drive a marked mile, or, 2. Use an external GPS unit that shows current speed. We chose option two. After set up was finished, the gauges worked flawlessly.