Why is battery draining?

[cb18201]

i am thinking about buying this 90 eclipse gsx but the kid told me something about the ECU draining the battery so he rigged up a toggle switch to cut off all power to the battery when the car is shut off. so everytime he shuts his car off he has to flip this switch, is there any way to fix this or does anyone know what the problem could be? thanks

 

[L2RTSiAWD]

Moved to Problem Diagnosis.

 

[SpeedFreak03]

There could be many things causing the battery to drain. Luckily, there is a way to figure it out. First hook up a multimeter between the positive on the battery and the battery wire (unhook the battery wire), and set it to find current (I think its current, its the one that tells how much electricity is flowing). Then pull each fuse, one by one, until the number drops significantly. It will always flow a little (for radio settings, etc), but the number will drop when you find whats really causing the drain. Once you find it, its a matter of finding the diagram for that circuit and tracing the drain! Yes its a bi***, id stay away, who knows what else has been rigged up.

 

[luv2rallye]

Until you know how much current is flowing, a multimeter in current mode is a bad idea due to it may either blow the meter (too much) or not show at all (too little for range selected). Also current can change drastically when you do things like when you open the door, turn key on, etc. A better way is described here "http://www.dsmtuners.com/forums/showthread.php?s=&threadid=54846".