Battery, alternator or starter on a C-Class AMG
One loud click with bright dashboard lights is the starter. Rapid clicking with dimming lights is the battery or a corroded terminal. Starting fine and then dying while driving is the alternator. We test all three at the roadside before fitting anything, because replacing a healthy battery on a Mercedes-Benz C-Class AMG with a failing alternator leaves you exactly where you started, two days later.

