battery light 1999

i just bought cougar 2days ago. when i test drive it was very fine.
then i was on the way to work, the battery lights start on and off on and off, i checked battery, it was nothing wrong with it. it start when i am driving. dose someone know, what is wrong?

alternator is probably on its way out.

thank you! i will check.

that just happened to me, my car died tonight, alternator that i replaced a week ago died on me again...

that just happened to me, my car died tonight, alternator that i replaced a week ago died on me again...

you may want to check the alternator relay. Usually when the alternator goes, the relay goes with it.

you may want to check the alternator relay. Usually when the alternator goes, the relay goes with it.

Check ur BAttery voltage before start the Car and after the car is started.

Before start = should be around 12v
after started = ur alternater should be pushing
voltage to ur battery around 14.5v

if its pushing more than 15 and less than 13 its a alternater problem replace the alternater will fix this problem. if its between 13 and 14v your alternate is good, Problem is somewhere else. Could me ur dashlight Battery bulb getting some kind a Ground . check the blub and wires.

MAKE SURE FROM ALTERNATER TO BATTERY WIRE
CONNECTION IS GOOD NOT LOOSE

Ok, my cougars had 3 pervious alternator changes i believe and i think its time for the 4th. brand new batter and car dies out. i replace the battery and check the voltage with the the car on and its at like 11.81 with nothing on, no lights a/c stereo whatever. i rev the engine and it jumps up to 11.83/11.84 so now how do i check if its the actual alternater thats bad and not a relay or cable? do i really need to pull out the alternator?

also i remember a while back, like maybe a year ago, i was jumping someone's car, and as i was reving my engine i remember seeing sparks shoot up agains the firewall from around where the alternator is.