I grounded the brown wire terminal, and tried to start it, no go. I checked the yellow wire with the brown wire terminal grounded and I have 12 V to the yellow wire when the key is turned to the run position, but still won't turn over by the key.
The yellow should only have 12 vdc in the start position, not run. That's what you meant to say?
If you have 12 vdc on the yellow wire, and you grounded the connection on the relay that the brown wire goes to, the solenoid must operate (click). If it doesn't, it is faulty. If it does click, and the starter doesn't operate, faulty starter, bad relay connection, bad starter connection, bad engine to -ve battery connection, bad relay to starter wire.
hopefully that covers it.