95 caprice elec problem

my caprice is acting up, runs fine until you use the lights, turn signals, brakelights, or hazards then it dies or when its not running my digital dash starts blinking when using the same. My gas gauge also reads full when its messing up. I was driving it one day and put the turn signal on, applied the brake and it died and it didnt want to run, it started up, sputtered into the parking lot. I started it a couple hours later it ran fine but I pulled all the fuses

check the alternator, it may not be recharging the battery and when you try to run more than one thing off the battery, it dies.

I HAVE THE EXACT SAME PROBLEM ON MY 96 9C1 FORMER COP CAR. I BOUGHT IT WITH ONLY 72k AND THIS PROBLEM HAS ABSOLUTLY KILLED THE CAR IT HAPPENS LIKE ONCE A MONTH AND LEAVES ME STRANDED RANDOM PLACES FOR RANDOM AMOUNTS OF TIME. IT DEALS WITH THE BRAKE PEDAL AND THE DASH ANDD THE RUNNING OF THE ENGINE. WHEN THE CAR IS MALFUNCTIONING THE TAIL LIGHTS DONT WORK AT ALL AND THE CAR WILL CRANK BUT NOT TURN OVER. IT SOMETIMES STARTS IN NEUTRAL BUT WONT GO INTO DRIVE OR REVERSE WITHOUT DYING. THE GAS GAUGE IS ALWAYS STUCK ON FULL WHEN THE CAR IS MESSED UP AND WHEN I DOES START THE CAR WILL IDLE BAD AND SPUTTER UNTIL IT DIES. THIS IS THE BEST CAR IVE EVER OWNED WITH THE WORST PROBLEM 2 MECANICS COULD NOT FIND THE PROBLEM SO I NEED ALL OF YOUR HELP. IT ISNT RELATED TO THE ALTERNATOR TO MY KNOWLEDGE. THANKS