[cabmandone]

Yep... yellow terminal. Those two smaller wires go to a smaller terminal that energizes the starter solenoid. Check red lead to yellow wire and black lead to ground at the ground strap.
The two larger nuts in the pic top one has a red wire and should have a hot wire from the battery. Bottom nut has a wire that goes into the starter. First check battery voltage. Red lead to large nut with wire from battery (wire isn't pictured in that picture) black lead to ground. Then with starter engaged check the voltage at the large nut that sends power to the starter motor.