2538 OBD port location

[Tee13]

Does anyone know where I can find the OBD port on my 2538 hst cab?

 

[duffer]

I have an open station 2538 and mine is right in front of the firewall, in the engine compartment. I suspect yours will be too. IIRC, it isn't "mounted" to the firewall, but just hangs by the harness wires.