1995 Lincoln Mark VIII Wont hold a charge

Does the battery go dead sitting overnight, or just for extended periods of time. Please advise.

I put a brand new battery in the car and overnight the battery was drained completely. The mechanic that did my tune-up told me to take the light out of the glove box, under the hood and trunk stating that sometimes they say on for whatever reason. I havent done this because I dont think this is the problem.

I figured that something staying on in my car even after it is turne off. I did notice that after I turn my car off and take out the key, the car can be turned on without the key being in the ignition. I dont know if this has something to do with it but I figured I would inform you.

The fact that you can turn the ignition without the key is probably in the key tumbler itself, and most likely have nothing to do with battery drain. The best way I know of to find your drain is with a simple "incandescent" test light. Not a neon or led tester. Disconnect the negative cable from the battery and connect the test light between the negative cable and the battery post. If you have a 12 volt (heavy) draw, the light will glow bright. Computer(s) memories only draw about 5 volts and will glow dimly at the light. First, with the key "off", disconnect the output terminal on the alternator to eliminate a possible diode problem in the alternator. If the light stays bright, start pulling fuses, one at a time, until the light goes dim. This will pinpoint the circuit that has the drain. Once you've found the circuit, it's a process of elimination on that circuit. Let me know what you find.

your alternator is bad the bridge is burnt out,even if it says it is charging,it is killing your battery.i had same problem,and it took some time to figure out.

The triode (bridge) could be be bad in your alternator. If the triode is bad, the alternator will charge just fine, but WILL drain the battery after you turn the car off. That is why I asked you to disconnect the output wire first before you make any other tests.

I have a similar situation I think. When I had the stereo on I could here a modulating electronic whining noise which rose and fell with acceleration. This has been a problem for quite a while. This morning when I went to start the car the battery was dead. When I put it on the charger I got a loud static sound coming from the stereo system even with the ignition off. Because I had had the problem with the radio I thought that it must be the problem so I disconnected it and the car started right up. However even with the ignition off and the stereo removed I still here the high pitch whine. I am wondering if that could be the alternator bridge issue. Any help would be appreciated

Hello, Ia m Danny.

You have attached a question to one that is years old.You need to start a new question including your vehicle info.Hope this helps and thanks for using 2CarPros.here's the link.
Danny-

https://www.2carpros.com/questions/new