Truck will not start it is missing Fl 80A ign sw

This fuse link is dedicated for you charging system. If this is missing then you will be running off just the battery and this will not last long. So clearly we need to replace that link in the fuse block.

Here are a couple guides that are related to this that may help others in the future:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

I am attaching the info below on this link and what it goes to. Please turn through all this material and let us know if you have other questions on this.

Thanks