I have covered 1,3,4,5,6,7,8. Like I said I have already replaced the solenoid and in doing so checked all the connections, power and grounds. The switch is on order so lets see how that goes. At this point the converter is working fine. When powered up produces 13.3v at the converter and the battery terminals when I can get it to latch. When not latched the voltage at the battery terminals are however they are charged.
I looked at the back of the switch and it has a 5 wire connector. Brown(one side of solenoid) , Red (12v), White (other side of solenoid), Green (?) , and Black (return/ground)
Not sure what the green does? Perhaps chassis ground?