I went to the movies and came out 1 1/2 hours later. I walked to the car, used the key fob to unlock doors and got in car. I put key in, turned power on but didn’t start the car. I rolled down the windows, responded to two text messages and then I tried to start the car. When I turned the key nothing happened. It was like I had a dead battery. All the lights on dash worked and door chimed. I tried a few times and then it basically drained out all power so it had no lights or door chimes. I tried to jump start the car. When I hooked up cables I got no door chimes or lights and car wouldn’t start. The electric mileage indicator wouldn’t even come on.
I had car towed to a garage. They said the battery was fully charged, had 843 cold cranking amps. They said the starter was getting power and they said alternator was good (not sure how they checked that without taking it off).
The garage replaced the main relay, ignition switch and ignition cylinder. Still no change.
Does anyone have any idea what I can try?

 

First thing to do is to clean the battery posts and cable terminals
Don't be fooled by clean looking terminals ... clean them
Also clean the grounding at the chassis
Then it is time to check to see if the fuse box is getting power
The battery cables may sometimes have fusible links which can burn out
Check all the fuses to see they are not blown and have power
Also look to see if there is a key symbol showing when cranking the engine.
When trying to crank the engine and it does not crank, try hitting the starter (lightly) to see if you can get to to crank