Why did my Ford Fiesta suddenly lose all power?

Our 2007 Ford Fiesta TDCi has an unknown electrical fault. The car takes a couple of seconds to start when twisting the key in the ignition and the headlights flicker a lot when that happens. Four days ago, the battery did not want to start anymore. We assumed it was drained, and maybe the alternator was faulty, so we just recharged it. It worked fine until yesterday. I put the key in the ignition, turned all the electrics on, put my seatbelt on then switched the ignition on and all the electrics cut out. No power at all, we couldn't even remotely lock the car. Half an hour later, it turned on as usual. There were never any warning lights on the dashboard.
It may well be a electrical earth problem. Try this. Disconnect the battery chassis earth cable (near the headlamps) and clean back to bare metal both on the wiring and also the body. Then reconnect with dialectric grease. You may also want to do the same to the earth strap between the engine and the chassis .
Answered by Alan Ross on

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