Car won't turn over sometimes

[richtazz]

You'll need a 12v test light when the starter is acting up to troubleshoot correctly. If you have power at the solenoid "s" terminal when the key is turned to start, you can eliminate the ignition switch and neutral safety switch as possible culprits. That puts the culprit as either a bad starter/solenoid, or bad battery/battery cable/bad starter. IF you "bump" the starter a few times with the key and it ends up starting, you have a bad spot on the starter armature, and a rebuild or starter replacement is the cure. Smacking the starter with a hammer as suggested above is only a good suggestion on older direct drive starters (it moves the armature off the flat spot causing the short allowing the starter to turn over.). Doing so on a newer style PMGR (Permanent Magnet Gear Reduction) starter will crack the ceramic magnets and ruin your starter. If you have no voltage at the "s" terminal of the starter when key is in start position, you have a bad ignition switch or neutral safety switch.