car all of a sudden won't crank over.

[tjdionson]

Car: 1996 240sx with s13 sr20det

Issue: Out of the blue my car won't turn on. I was troubleshooting a squealing belt, so I was turning the car on and off several times. Thought it was my power steering belt, but finally figured out it was the alternator belt all along. Made adjustments, turned it on, but squealing was still there so I turned the car off then tightened the belt a bit more. Tried to turn the car on and nothing. After trying several times, all electrical power was gone.

Things I checked:
-Fuses
-Bought new battery

New battery in, same issue. Have power when key is in "on" position and confirmed power to ecu. When trying to start car, I only hear a single click and if I do this multiple times, I lose all power. I have to disconnect the negative terminal to the battery wait a couple of minutes, then power comes back on. I'm at a lost, so any help would be greatly appreciated!!!!