1. Are you pressing the clutch sensor in when trying to start? You can also select neutral by moving the big block shifter on the trans to the middle spot. There should be 3 distinct spots; forward, middle (neutral) and back. I think I still needed to press the clutch sensor even with neutral selected. This lever is the one on top in my photo below.
2. Does one of the wires you have going to ground connect to the starter?
3. Do you have the ECM hooked up with the three connectors? In the early photos it didn’t look hooked up.
4. Are you watching the videos about hooking up connectors and wires? It steps through everything decently well. Good enough for my electrically illiterate self to get things running.
5. Do you have the power steering harnesses plugged into the unit? Same with turn signal switch? Some (mine included) needed these hooked up to complete the circuits. I would hook everything you can up, dash, BCM connector, turn signal switch, brake sensors, clutch sensors, etc. The only thing I didn't have hooked up was the DF aftermarket button panel kit, headlights, taillights and turn signals.. This has the horn, hazards, cruise buttons that surround the gauge cluster.
6. When you turn the key to run (not firing) does the throttle and HX fan come to life?