Originally Posted by daveselwood
put a multi meter on batt terminals it should be about 12 v dc,start engine and rev car abit while reving it check meter it should increase to about 13 or 14 v ,if it does this ok then you need to get batt tested,have you checked water in batt o is it sealed
I havent checked the water level in the battery but could this be the problem. I've got cossie management on the fiesta and got a secs monitor fitted. This does show a starting voltage of about 12v and today was showing 13.5V when the engine was idling which drops to under 12v when the lights etc are switched on.