Q: Horn repair cost.

The horn is a pretty basic circuit on your truck. The most common causes of a horn failure on your truck are the horn itself, the horn button, or the body control module. If the horn does not work at all, even with the remote door lock, then it is probably the horn. If it works with the remote lock and not with the horn button then it may be the button itself. A mechanic would need to check these conditions and then check for voltage at these components to find the failure. Depending on what the problem is will determine the cost. I would recommend that you get assistance from a certified mechanic, like one from YourMechanic, that has the tools to do this.