My car won’t start. I have changed the battery, checked the starter and alternator and had it hooked up to a computer. The computer read no problems. My lights, radio, and windows still work.
I have created a step by step diagnostic chart for just this issue.
Often times you will need to check to see if you are getting battery positive voltage at the “S” terminal at the starter while someone is holding the ignition in the start position. This is a good way to test that the problem in in the starter or in the circuit before the starter. Could be as simple as a blown fuse or failed relay.