Why my 1997 mercury cougar lost all power
well the battery was dead. , the starter is dead and fails to crank then engine. (turns over has no meaning,some say cranks other claims runs means turns over )
but I get it the starter motor is dead
then jumped cabled after 10min the dead battery is now just tad charged up but you removed the JUMP and the engine stalled I guess..
lights use only 10 amps of current , but the starter need 30 times more current and fails. 300amp to 500 amp hr battery is bad or lugs rusty or loose.
or the alternator is bad .
the cluster lamp , has charge/ battery lamp if this glows after the successful jump. the alternator is bad. (or belt to it failing/slipping)
keep in mind an alternator switches off line if any battery gross fault is detected (shorted battery cells or open)
batteries with shorted cell explode (acid rupture max)
batteries open cell (10v battery )the voltage can go so high over 19v
that electronics blows up, $1000 or more, damage
so the regulator takes the alternator off line , until corrected.
saving everyone and every thing from those horrors above.
what I do is fully test the battery first, charged and load tested.
or take to a autostore or shop and test it.
the battery they love to fail 5 to 7 years old.
that is there THING , short lived. same with belts, tires, hoses ,pads
tests are easy
get the battery load tested
or charge the battery fully using a real battery charger 15amps, best.
and test the alternator, after good battery works and starter works and engine runs
battery voltage running is 13v to 15vdc, if not the ALT is bad or its 3 fuses blown.(up to)
key off battery voltage fully rested battery say 1hour, is 12.6vdc,not 10.
also a weak battery can wake up, as they rest and the acid mix inside
the cells gets uniform it can gain capacity. this is common.
just key off ,lamps off, and battery can self improve.
if start is dead , learn to crank not just in park but try NEUTRAL.
bam it crank,s.