The battery in my Ford Mondeo is only showing 12.3V - what's wrong?
Recently, the fan belt, tensioner and battery light came on in my 2004 Ford Mondeo. I had belt and tensioner replaced, but battery light still. I checked the battery voltage for charging, with the engine running, but it's showing a voltage of 12.3V.
If you only have 12.3V with the engine running then your alternator has failed and needs replacing.
Answered by Alan Ross on