Its been a few years, but the splice I'm talking about is located right in the brake booster area. I'm just not sure which side of the booster it is on.
It is a splice, factory taped, either pink wires with a blue tracer, or it is blue wires with a pink tracer (I really think mine were pink). There are 3 or 4 wires (all are small wires probably 18G) on one end and 4 or 5 on the other end. The wires all joined at this splice then ran to each sensor individually. these are small wires, and I suppose they could have each broken individually, but I would follow back to the splice.
You need to open up the corrugated plastic, locate the bundle of pink/blue wires, remove the factory black tape and pull on each wire to see which one or how many are broken off. On all 3 trucks I encountered, this issue, every one had bad corrosion (the terminal had a green power tint like battery corrosion to it). Those wires supply ignition voltage to the cam sensor, the crank sensor, the dist hall effect piece, the coil, and the computer (I think), and something else. If any of those sensors do not have voltage to them with the key on, this splice is your problem, but one of the trucks had voltage, but it was lower then normal voltage (probably due to the corrosion).

The only factory service manual I have here is an 87, and those were still carburetor fed motors, so this splice is not shown. I suppose you can open up your harness, start at the coil, or cam sensor, or dist pickup wires and follow the wires to the splice near the brake booster.

I removed the factory splice piece, stripped all the wires and re-spliced them again with one connector, then taped everything up and we were good to go.
Gene