Answer

Hello. There are three possibilities: bad wiring connection (most lilely), bad solinoid, or bad starter. You can test the starter by using a jumper cable to connect the battery + side directly to the starter terminal - if it runs then the starter is good. Next, try jumping across the two large terminals on the solinoid - sometimes the blade of a screwdriver can be used to do this. If the starter runs then you have a bad solinoid. If the first test works and the second doesn't (i.e., the starter runs when jumped from the battery but not when the solinoid is jumped) then the wiring from the battery to the solinoid is bad or there is a loose/dirty connection. Also, make sure the neagive battery cable (black) is also clean and tight on both ends - that cable can also cause the same problem, so check it first.