Start by cleaning up the corroded cables with baking soda and water and a small wire brush.Also have the battery and alternator tested a multimeter cannot properly test a battery.Thats where i would start.

Answered by saturntech9 (expert)
23,192 answers provided

Make these measurements when the problem is occurring. In particular, Fords have a lot of trouble with wire strands corroded away under the insulation where you can't see it, right where the large cable bolts to the starter.

When you get the fuzzy stuff growing on the battery cables, the battery is going to fail within approximately the next six months. So much of the lead has flaked off the plates that what is left overheats causing the acid to bubble excessively. That bubbling reaches the top of the case where the acid sneaks through by the posts and causes that corrosion. Cleaning it off is only a temporary fix.

Answered by caradiodoc (expert)
17,324 answers provided