My battery on a 99 mercury grand marquis has a short and i have to keep the terminals unplugged while car is off or it will drain and wont start
That can be a tough problem to solve. You'll need an Ammeter and schematics, hook it up to see how many amps are being drawn, pull fuses one-by-one until the draw goes away and fix the problem on that circuit. I have seen quite a few alternators that draw current when the engine's off. If you suspect the Alternator you can have it tested at most parts stores.
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