I have put everything back together and I don't have spark but I detect 12v going into the coil. What triggers the coil to spark?

 

TFI module, through the PIP signal from the distributor.

 

I thought I wanted to replace the TFI module so I took it out and looked at the connections. I decided before replacing it, I'll clean both ends. It did look a bit dirty. I also replaced the coil with a backup I have so one of those two things started the truck after about 1 second of cranking. Much better, more like it was. Haven't let it warm up yet, need to button things up a bit more.