There seems to be lots of juice in the battery - lights, interior lights, radio etc. I turn the key and the lights go dim - there's a single click and some sort of buzzing/whirring noise like a solenoid is discharging. I tightened the negative terminal but that did nothing. The odd thing is that I went back to it a few minutes later and it started fine. I turned it off and tried it again and the same issue occurred. I'm thinking either battery or starter. Thoughts?
My car has an automatic transmission.
This may be related to a faulty starter solenoid. The starter solenoid is located on the starter and has internal electrical contacts that transmit electricity to the starter. When this fails, it may cause a clicking sound and will not allow the starter to engage the flywheel when you turn the key. I would suggest having a professional from YourMechanic come to your home to diagnose your starter.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing