IM having a problem starting my truch

You may be hearing the starter relay clicking once each time you turn the ignition switch to "crank". Start by using a test light or voltmeter to test for 12 volts on the smaller starter wire when a helper turns the ignition switch. If there's no voltage there, put your finger on the starter relay and verify it's clicking. You'll feel it. Also push sideways on it slightly. If that makes it crank, the terminals in the socket are spread and need to be squeezed tighter.