When I hit the brakes the entire cars electrical turns off. I’ve checked wiring and there’s no shorting out or crossed wires and all insulated well. Any clues?
I would disagree, the evidence suggests you do have a shorted wire. You just haven’t found it. Good luck, this will be difficult to find.
Thanks in my heart of hearts I thought so too.
Also check you engine mounts. Under braking, the entire engine shifts forward. If there isn’t enough slack in the wiring harness, it can tug a wire out of contact and kill the ignition. That could be very difficult to find. You can test this theory by starting the car, putting it in reverse and press on a the gas while firmly holding the brake. With the hood up, you should see the engine rock forward no more than about 1.5 inches at the valve cover. If it stalls you may have a hint as to your wiring problem. If it moves farther than a couple of inches, diagnose a bad motor mount, too.