My 99 Yukon has a reoccurring no crank/start. The only way it starts is by jumping the two starter nodes. Any suggestions

How old is your current battery? Have you cleaned your terminals and grounds? Sometimes the corrosion creeps up the positive cable under the protective coating. Cut a little off the positive cable and see if the corrosion is working it's way up through the cable. If all looks good, I would try a new battery if you're not sure how old your current one is. If it will start by jumping the starter, it sounds like you're not getting enough current all the way down to the starter. Post back with results.........

I'm jumping starter from starter node to node including wire from battery in the circuit. The battery is 1 year old and i changed negative screw two days ago. I believe it's good. Just problems with initiating start up with key. Wires are tight. Checked all fuses. Still not starting from ignition

Is there a fusible link between the starter and the ignition? Have you tested the wire for power when turning the key? Here is a video that will show you how to test and diagnose your issue. https://www.youtube.com/watch?v=fpPOcO6f798

Thank you for video. it reaffirmed starter isn't problem. Wires, ignition or neutral safety switch seem to be the problem.

It was neutral safety switch!!!! At firsr I repaired an exposed ignition wire near starter. Still didn't start. Nuetral safety switch was $35. And my last resort before seriously considering giving up. Top harness is a beast to remove (both are really) I believe safety switch was cracked already but I totally ripped it to get to mounting screws before I could remove top wires long story short truck is running great. Thanks

Good deal! $35 bucks sure beats paying the local shop $800! Nice job!