The threaded post,Is for battery cable positive.The small connection wire ,Comes from safety switch under floor board.Battery power supply wire to ingnition comes off positive post at battery.Their was no factory relay in wiring,That i know of.However ,some relays where installed by machanics.To insure a ture 12 volts.At energizeing connection at solnoid.

I know that on some of the older Nissans', (which Datsun were assimalated into), there is alittle brown relay under the floor board on the left side for the starter. Give atry and look.

I know that on some of the older Nissans', (which Datsun were assimalated into), there is alittle brown relay under the floor board on the left side for the starter. Give atry and look.

I have been installing Ford style pre-start solenoids on all of my early Nissans, this has been taking care of a lot of intermittent starting issues. Take the push on terminal and see if you have 12 volts when the key is in the start position and and lever is in neutral, then take that terminal off and install a ring style terminal on the wire, then hook this wire to to the small terminal on the solenoid, put another ring stle terminal on the other small terminal of the solenoid and run that to the chassis for ground, then take a 12 guage wire from battery positive to large terminal of solenoid, then run another 12 guage wire from the other large terminal of solenoid to the starter energizing terminal on the starter solenoid, where the push on terminal originally went. The heavier guage wire has cured many starter issues for me lately. I have installed a couple of new starters that just went click when you hit the key and the heavier wire has cured the problem. In fact Cat started doing this as an update for their GM 4.3 starters that were being replaced unnecessarily, they added a heavier guage wire from the starter relay to the starter.

Working on memory- I believe that on the starter- the 1 threaded stud had the battery cable & feed line for the charging/power supply for the unit, the other stud had the feed line for the starter brushes. The slip on terminal was the feed line to energize the solnoid.

I remember 1 relay- the horn relay, in the wiring. There were no relays in the starter circuit. The starter circuit was quite simple- fron the ignition switch, to the nuetral switch, to the starter solnoid.

If you have no power at the solnoid, check the igntion switch, then the nuetral switch, then the connector on the left side of the cowl- that used to get all corroded- at some point I used to just cut it out & hardwire the wires together.