Nissan Repair: 1990 Nissan Truck, neutral safety switch, nissan truck

Question
My husband is working on an old 1990 Nissan Truck.  He has
installed a new starter and a new batter, but the engine still won't crank with the key is turned in the ignition.
He knows it probably has to do with the electrical wiring.
How can he get a wiring diagram for the starter.  The truck has a manual transmission.  Any help you can give will be greatly appreciated.
Thanks

Answer
Hello Sandra -

First of all, get a 12V circuit light tester and touch the probe to the small terminal of the starter. If it lights, then you probably have a defective starter.

if it does not light, I would check the neutral safety switch, ignition switch, fusible link (do the headlamps work?) in that order. You can check the nuetral safety switch the same way as the starter. Check power when you turn the ignition key. It is located on the transmission.

Hope this helps -
aloha
calvin