my truck wont start or even click

Your battery may not be charged enough to turn over the engine. If it is dead it will not "click:. First as asked above, do you have other lights and functions that work? If the battery is not charged enough, the relay may not send power to the starter. check cable for tightness, and corrosion. Clean all contacts. Will it start with a jump? If so, how is the alternator charge? If it is good, that part is fine. If the battery will not then start the car after sitting over night or even right away, have the battery tested. New batteries or even some a few months or a year old go bad in a cell. If the battery, charging unit, cables and connections are good, next start on the electronics ans see if there is a code that will tell you why it is not allowed to start. Cables, connections, corrosion, battery, jump start. That order. work up and out. Electronics should be the last to check, but do the code read first if you can get it started.