Q: Engine starts cranking without key when hooking up battery

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Battery died about 2 months ago. when jump started 2 times, started normally. When jump starting 3rd time, engine turns without key in ignition. Then bought new battery and when hooking up, engine still starts cranking without key in ignition. Need to troubleshoot and fix problem. Please advise.

My car has 120000 miles.
My car has an automatic transmission.

Hi There, What you are describing sounds like a faulty starter solenoid or a bad ignition switch. A faulty starter solenoid will generally produce a clicking sound when turning the key. The starter solenoid is located on the starter and has internal electrical contacts that transmit electricity to the starter. As electricity is supplied to the starter a small gear comes out and engages the flywheel to spin the engine over as you turn the key. When this fails, it may cause a clicking sound and will not allow the starter to engage the flywheel when you turn the key. When your ignition switch fails, this may cause any of the ignition circuits to remain active after taking the key out of the ignition. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

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