Replaced ICM and coil , starter cranks engine, but no spark. The repair manual is vague about location of fuses , fusible links. What does a failed fusible link look like? Do any of the fuses under the dash control the ignition? There are a lot of small , plug-in modules in the engine compartment wiring harness, are any of these fuses or controllers ? I'm doing that inept mechanic approach of replacing things till it works. Is there something else I should check?

When you have electrical problems with your vehicle, one of the first things you want to do is check all underhood and underdash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-t...tml#post252145

You really shouldn't have to worry about fuses beyond these two fuse boxes.

Took cap off dist. rotor spins when cranked. Getting 12v. To coil when ignition on run position. Checking under dash fuses, fuse block is loose, only one screw holding it in. A 15a fuse was laying on cover, it looked distorted from heat, but continuity checks o.k. on it. There is a thin gauge wire plugged into fuse slot (previous owner install?), other end was loose but it looks like it was attached to ground, sparks when I touch it to ground, purpose unknown. Could the under dash fuses keep it from starting? Lot of background noise, traffic & jets, not sure if fuel pump is running.

Underdash fuses could definitely prevent it from starting. You need to get a fuse layout for your fuse boxes and determine how things should be. Sounds more and more that your problem is related to the fuse box.