how can i check my altenator and battery? i have a lexus es 300 1992?

[Mike]

the battery is not holding the charge and every time that i leave my car over night it wont start i dont know if is the battery or altenator how can i check it?

[Lover not a Fighter]

Take it to Autozone or Sears and they will test both for free.

If you must test it for yourself, get a voltmeter. With the engine running, the voltage across the battery should read about 15V (14.8v). If it is above 16 v or below 13 volts - the alternator has failed. If the alternator is fine, then the battery is NOT holding charge so it must be the battery.

NOTE: often when the alternator has failed, that will cause the battery to stay discharged long enough to weaken or fail the battery.


Good Luck...