Battery keeps draining out on 1995 Cadillac Deville

I suspect parasitic draw. All vehicles draw some power from the batteries when the car is shut off. Certain accessories such as clocks, radios remote door openers and alarms always need power. The normal power used is called parasitic draw.

It is always a very low draw so it doesn't run the battery down. If you install accessories like shortwave radios or plug things like inverters and portable refrigerators into the accessory socket and operate them too long without the engine running you can drain your batteries to the point where the engine won't start. If there is an electrical short in the vehicle or a malfunctioning accessory it could be drawing much more than its normal load causing a drain on the batteries. If you leave your door open and the inside lights stay on all night you could drain the battery down till the car won't start.

Here's also a good resource for your car specifically on narrowing down the cause of the drain.

its on the side of the radiator ,down towards the bottom of it,,on the drivers side,be care full because this stuff will gush out of it if you remove the drain plug all the way,and you need a good sized pan for it because it holds a lot of coolant,good luck,i hope this helps

Have your alternator checked at an auto parts store. It sounds like it isn't keeping up with the drain on yuor battery.

Have Auto Zone load test the battery and check the alternator. It free of charge and they will tell you which is bad

relay time.

replace the blower control module.

I stated "such as a light " there are many, many other causes of 12 volt drains such as a seat switch that might hang up and stick. Empty that battery overnight. First install a 9V Battery Radio memory / and clock or you will have to reset both. Disconnect BLACK negative cable of battery. Using a 12V testlight, connect one end to the disconnected cable, and the other to the negative battery terinal. It should light. Remove the 20A BODY and LIGHTER fuse first . This will eliminate the courtesy light circuit . If light goes off the drain is on that circuit. STILL LIT ? drain is on another circuit. Start by eliminating fuses. Hope this helps.

CHECK THE FUSE OF THE ALTERNATOR OR CHECK IF THE ALTERNATOR IS CHARGING

look for fuse for alternator and the DRL.

have the alternator checked it could test good and still be bad but it can also drain the battery 9 times out of 10 its the alternator thats draining the battery