Originally Posted by
cadunkle
Get out your multimeter. If you have +12v to the ignition switch constant hot terminal you're golden for both start and run from the switch. Check voltage at the stsarter solenoid actuating (usually labeled S) terminal with the key in the start position. If so, problem is the starter or solenoid, which is unlikely since you can start it by jumping the solenoid. Check continuitiy from the start terminal of the switch to the start terminal on the starter solenoid, you likely have no continuity. If that is the case, repair the connection at whichever end is broken or replace the wire. Could also be dirty or corroded at one end.