Learned this in my Electrical Class. Any car that’s about 5 years old probably has some rusted/corroded ground/chassis connections. There are a number that are super important in most cars: battery, alternator, starter, computers. Follow those and mark them. Then disconnect the negative cable from your battery and isolate it (use a thick rubber glove or tie back). Then disconnect the grounds and clean them, the car, and the connecting bolt with a wire brush (I use the Dremel attachment). Reassemble and reconnect the negative terminal of your battery. You’ll save yourself countless batteries, alternators, starters, and computers.