96 Blazer wont crank--Help

My guess is the problem is in the start circuit. But trouble shooting is tough without a factory manual, all I have is a haynes and they su0k. The selonoid doesn't get power in the start position But the truck will crank and start with a 12v jumper to the selonoid. I tried moving the gear selector around but still no crank. The 96 S-10 is the girl friends and I don't know where the neutral safety switch is to check or what else I should check. Any input will help as today was to be a day hanging my new heads on the L98 in my Jag. Update: found a fuse marked crank and the fuse is good but doesn't have power in a crank mode? Also after a search here I think I found the neutral switch on the tranny, plastic gizmo with a couple of plugs on the shifter shaft? What wires come into play? TIA

Did you check the battery voltage?

Did you clean the connections to and from the battery and starter and solenoid?

Did you check the battery voltage?

Did you clean the connections to and from the battery and starter and solenoid?
Yes that was the first thing I checked. I have since then checked for a cranking signal (12v) yellow wire at the neutral safety switch. There was none so I would think I have to look / test up around the ignition switch. Now the question since I did use the search funtion is the harness or the switch the first to look at? The girl friend can use her truck for school to-nite since I ran a fused 12volts off the alternator thru a button switch and down to the selonoid. If it was mine I would just leave it that way, but I'll have to fix it the right way in a few days. It does seem her 91 S10 gave me less headaches and was a lot easier to work on. JMO