1995 crown vic Dead battery

[mcdlnwright]

Ok guys and gals,

1995 crown vic Regular issue

got up one morning and the battery was dead, jumped it off and went about my day.
Was fine for 5 days had my two off. went o go to work and it was dead.
jumped it again.
Took it to Da zone and they tested teh battery and said it was weak but good.
said the alternator was ok but to be sure I would have to take it off and bring it in for a better test.

Took it off and the guy said well its not completely dead but dieing. its putting enough charge to drive but not enough to charge the battery.
So I replaced the Alternator. and Wally world gave me a new battery..
I replaced the plugs and wires while I was there and all was good in the world..... or so I thought

Went on vacation came back 6 days later and the battery was dead.
jumped it off went to work and left for the day and it was dead again.
jumped it off and its been fine for a fw days of me driving it every day.

the true test ill be tomorrow after my two days off

so what the heck is going on?
what am I missing

[cmsorrells]

mine di that but mine was cause of a bad alternator

[mcdlnwright]

Yea thats the thing I already replaced that and the battery

[Selectron]

If you have a new alternator and battery and the wiring between them is good, so the battery is receiving normal charging current, but you're still ending up with a flat battery when the vehicle is parked for a few days then it's likely that you have an excessive residual current drain.

A low level of residual drain is normal, as current is required by the clock, the radio presets memory, the alarm system and probably by some of the engine electronic control modules, to retain stored settings. On my car (UK diesel Escort), that's 30mA (0.03A), but on some vehicles it can be as high as 70mA (0.07A) - anything above that level would be a cause for concern.

If you have a multimeter then set it to its highest DC current range (usually 10A), remove one of the connectors from the battery (doesn't really matter if it's the positive or the negative) and insert the meter in series and observe the indicated current flow - on some vehicles it may take a minute or two to settle to its steady-state level. Prior to doing that, ensure that everything is switched off - i.e. ignition off, and if you have under-hood illumination which works when the ignition is off, then remove the bulb, and close the car doors to prevent the interior courtesy lights from illuminating.

Common causes for excessive residual drain would be the glove compartment lamp failing to extinguish when the door is closed, interior courtesy lamps or trunk lamp failing to extinguish, etc. It can also be caused by leakage current in faulty wiring or components, or by a faulty diode in the alternator rectifier pack.

If you don't have a meter then you can use a 12V test lamp, inserted in series in the same way as the meter. The higher the current drain, the brighter the lamp will be, but that's not really a great way to test current drain so a meter would be preferable.

If you find you do have excessive drain, then start to remove and re-insert fuses one at a time until you identify the circuit which is causing the problem.