i have a 2000 montero sport xls battery drain over nite is there way to find out what cause the problem please help.

This is hard to diagnose,but it can be done,most of the time it is alternator,or something electronic not shutting off,such as interior light,s,stereo.

The battery is bran new the voltage drop from 12.64 to 12.40 from just open the door for about 10 seconds.

So is there a way to find out what cause the the problem? Please help.

And how to load test the battery

Do a parasitic drain test. http://www.youtube.com/watch?v=zdIKNnwEjIs -- http://www.youtube.com/watch?v=P-wxG6U5TuY and an auto parts store will load test your battery ..and It's 15 years old and look as well as you can at where the wires go from door to chassis, from thousands of open/close door they can begin to fray

Thanks mark.

On your model mitsu. The voltage regulator in alternator will go bad and cause this,but i agree with fordnut,check the wiring in the door jam,s,all so.Like i said above,it,s hard to diagnose with out,testing all current,from fuse block,that will lead you to the fire,going out,and who know,s ,you may find it to be the igintion .

None of us are 'Mark" That's what you click if the answer was of any help/ No worries, happens all the time

But fordnut,,: ) my name is really mark,and the hole time why posting answer,s,,they have been saying,,Thank you mark,,,,im like how????You have solved the mystery.

HA! I didn't know your name is Mark...but that happens...