Ok so I looked all over the internet but I couldn't find anybody who had even an remotely similar problem so here we go. I recently changed my 1998 gs400's battery. Before tightening the positive pole, I just dropped the battery mount on it to check if everything was find before I tight it in place (so it was loose on the battery). When I got in the car, the radio worked, gauges lighted up, etc so I turned the key farther to start it and then "click", everything shuted down. I tried to connect the battery to a fully charged booster pack without any luck. Now, the car is just completely dead. I probably toasted some kind of fuse somewhere or an ecu. Do you have any suggestion for me dear members?

 

I say check connections again. Check the wires and how they're attached to the terminals.

 

I just went through this, it was a loose battery terminal. If your accessories work that's probably what it is. If you don't get any lights/radio then I would dig a little deeper.

 

Yep that was it aha I just noticed that thank you!