'95 240sx power drain when key is turned on.

[s14280zx]

I went to go to work this morning, and my battery was dead, so I jumped it and went to work. When I got back, it was dead again, so when I got home I checked it with a voltmeter. When the car was running it read 14.2v . When I turned the key completely off, it read 12.5v. But as soon as I turned the key to the on position, the voltage quickly went down to 8-9v. I started unplugging the fuses under the hood, and when I unplugged the big green 30 amp fusible link for the ignition,(the one furthest toward the front of the car), the voltage went back to 12.5v. There are two wires attached to the fuse, both are white and red. The one wire is the driver side one that plugs into the positive battery terminal. When I touch the fuse to the contacts, I hear a clicking noise coming from the starter area. It sounds like a relay clicking or something. Any help would be appreciated. THANKS
Modified by s14280zx at 6:29 PM 8/7/2006

[JeromeS13]

Sounds normal, except the 8-9volt part. Chances are, your battery is really weak. Get it charged by an actual battery charger, have it tested, or buy a new one. Its perfectly normal for things to draw amperage from the battery when the key is in the ON position. But, if your battery is weak, that would explain the drop in voltage.

[s14280zx]

Thanks for the help. I'll try getting a new battery, and let you know what happens.