If battery is weak put it on charger less than hr truck cranks now wondering if it is alternater
Test alternator it should be putting out around 14.5 volts or so.
Ok, it cranks but does it start? Is that what you are asking about? Also, when battery is a bit down test you alternator for Amperage output also, being careful not to fry your multi-meter, be sure it's on right settings
Looking for a Used F-150 in your area?
CarGurus has 230,829 nationwide F-150 listings starting at $1,300.
Search Ford F-150 Questions
Ford F-150 Experts