Can't start my 94 zj, think it's anti theft related
So my car has been working fine and all the sudden I cannot get it to start I am hoping that someone can shed some light and help me get it working.
Problem: Get into to start vehicle and all electrical is acting normal until I go to turn it over and you here the starter click then all power shuts off. After that there is no lights, power locks, power windows, etc. If I disconnect and reconnect the battery all power is restored but when I try to start the car again I get the same problem.
I tested the battery and it checks out fine, don't think it's starter related because all the electric shuts off when I try to turn the key and checked the main wires and they seem ok. I think the anti theft system is malfunctioning and that is why I cannot start it. There is some sort of relay box located behind the battery that comes out of the positive wire bundle and it is very corroded. I cleaned it with some battery cleaner and it started for two days and now I have the same problem. I don't even know what it's called to order it. I am going to try to ground the anti-theft system but am kind of at a lost.
Please help with any suggestions