Check to make sure you have the correct adapters to fit your units' diagnostic ports, and that you have the same number of ELDs as the number of adapters. Below, the different adapters available are shown along with their product (or material) codes.
Best Practice: The ELD should be mounted in the vehicle in a place where the ELD has a clear line of sight to the sky. This location is ideally on top of the dashboard, as the LED indicator lights are also visible to the driver.
ELD Quick Start Guide (Including Installation, Initial Set Up and Configuration)