Battery issues - electrical short

https://shoptoolreviews.com/automotive/diagnostic-testing/parasitic-battery-drain/34587/

Way to many diagrams to guess to send. What components are working. Check engine light on?

have battery retested-or ac electrical for parasite drain

I can't come and diagnose your car, but there are 2 things that might help.
First, if you will disconnect your battery each time you are finished driving your car, the battery will not drain overnight. You will need to re-connect it to go somewhere.
Second, there is an electrical item that is turned on, that is not turning off, or, there is a short in your electrical system.
When, in the morning or whatever, you hook up your battery, if there is a spark of any size at all between the battery cable and the battery connection, you know there is a short or something left on.

Someone will need to check the circuits in the car for a voltage drain.
A mechanic would pull the negative battery cable and use a test light to check for a power draw on each circuit. Could be a relay or other electrical component with a short to ground. Could also be a small courtesy light left on.

Thanks for choosing FixYa and welcome. I would start by checking the alternator and battery out. Even though the lights are on, the battery can be too weak to crank the starter. Check your ignition fuse also. Sounds like a power issue so check all your battery wires and terminals/post out. May have a bad connection. Make sure it is not loose also. I would say check the alternator first cause it can kill the battery as well.

I would suggest you take it to an autoparts store and have them test both the battery and the alternator to find out which is giving you problems. If both are good then you have a short somewhere in your electrical system that drains your battery overnight. Which would take a clamp on ampmeter to localize.

I have a 2002 Lesabre and would suspect it is the same. The 2002 has two fuse blocks. One under the hood by the jump start peg and the other is under the back seat by the battery. My manual shows the #1 fuse in the block under the seat as the fuel pump fuse. I would look there first. If blown, be prepared for another as something caused it to go out. Perhaps a short in a wire.

It sounds like there is a short or something...something is drawing power constintly and draining the battery. Something like this is usually hard to diagnose and requires a lot of electrical testing to determin where the power draw would be coming from in order to fix the problem. I would say u may need to have somone test your electrical connections and whatnot to find the source of the problem. Hope this helps any, good luck!

Electrical problems of an intermittent nature are the most difficult to solve. It sounds as if something is draining the battery. The charging system needs to be checked with diagnostic equipment. Something like a parasitic drain may be causing the battery to run down and the alternator cannot keep up with the demand. When something like power windows are activated, they draw a higher amount of current to get started than they need to keep rolling, and this surge of energy may be robbing the injectors of the current they need to allow fuel delivery. I experienced a problem like this on a customers car, and we found that the trunk light was staying on when the lid was down. This was enough to keep the battery from becoming fully charged, and the alternator had to be replaced from being over-worked.