The stud on the side of the starter is a ground , so check the wires you have with an ohm meter , to see zero ohms to the frame or battery negative post , for the wires that go to starter ground stud .
The alternator power output goes to the side of the solenoid with the main power cable, and a power feed to the starter relay. Alternator ground also attached to the ground stud on the starter.
Page 4 in this pdf . For what ever reason the pages in the pdf are mixed up , look for page 4 of 6 in the lower left of the page , for the Cat starter/alternator/battery wiring .
Don't know if Freightliner was still using Denso starters in 2003 but here's pictures of my starter . Note I have added an extra wire to the solenoid activation terminal to by pass the starter relay ( that has failed twice on me
) I did repair the oil leak , but haven't got pictures with the wiring cleaned up .
I'll be under the coach doing heater hoses , so if these pictures and schematic don't help I can take better ones.