Client had a Mitsubishi Forklift with a Perkins engine. He was attempting to connect one of our off-highway diagnostic tool to it. The customer had looked all around the engine compartment, and could not find it. He checked everywhere near the engine ECU, and no luck.
Sometimes these are really hidden. We instructed the client to remove the instrument panel, and behind it we found the connector under the cup holder. Once connected, the customer was good to go.
To us, this proves the point that you need support to help you. Having a diagnostic tool isn't enough!