what is causing my battery to drain if i don't drive it? on 1997 Mazda Miata MX-5

i've replaced the battery at least 4 times since 2007. if i don't drive the car for at least a week the battery is dead, and can't be recharged. i've been told it is not the alternator but a short somewhere. what is causing a short and how do you isolate it and fix it.

Asked by for the 1997 Mazda Miata MX-5
The easiest way to check for a "battery drain" is to disconnect the negative battery terminal and connect a test light between the terminal and the cable. Do this with the key off. If the light lights you have a drain. To isolate you start taking one fuse out at a time .When the light goes out that is the circuit that is causing the drain. You will have to refer to a wiring diagram to see what is in that circuit to isolate the cause
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The term 'short' is very general. It can be many different things causing a power drain. The best way to find what is causing it is to have an ampmeter and correct wiring diagrams. It could be as simple as the trunk light staying on , or a faulty relay stuck on. Proper circuit info (including description of how the circuit operates) is key , to avoid a lot of guessing and extra work.