Help! Truck is dead after negative battery cable melted

[BlackMJ90]

The long and the short: my horn has not been working. I installed one on the passanger’s side (there wasn’t one there) and used the existing pigtail to plug it in. Instead of getting a working horn, my negative battery cable melted and the truck died. I replaced the negative batery cable and still nothing. The truck is getting absolutely no power and it will not jumpstart. I haven’t fully inspected the positive battery cable because it got dark but from what I could tell it is totally unaffected. What could have shorted out that would cause the truck to lose total power? Please help!

[Ωhm]

Need to check your fusible links.

[BlackMJ90]

Hate to sound like an idiot, but where do I even start with that? Where are the links that would cause the truck to have no power whatsoever?

[Eagle]

Your '90 should be close enough to the '88 for this to help:

 

http://www.bteventures.com//mj1988electricalmanual.pdf

[omega_rugal]

did you touch something else when you installed the horn? the only way yo melt a cable that thick is by shorting the battery... btw what about the battery?

[cruiser54]

Fusible links are located at the starter relay.

 

 

[gogmorgo]

A poor connection between the battery and cable (or cable and clamp) could heat up the terminal pretty severely. 

Theres not a heck of a lot that would pull enough power to cook a battery cable without melting down what would surely be a much smaller positive wire first. It's pretty much a guarantee your added horn didn't do that. Really the only way would be shorting to an equally massive positive cable, and unless there's aftermarket equipment added, the only one is the one going to the starter. Easy enough to check.

My money's on a poor negative connection.