1988 Lincoln Mark

I BOUGHT THE CAR FROM A INDIVIDUAL. IT IS A USED CAR DEALER IN MAYFIELD KY. THE ABS BRAKE STAYS ON, NOW. I ONLY HAVE FRONT BRAKE'S. SOMETIMES THE BRAKES WORK, I GUESS.THE PEDAL GOES TO THE FLOOR WITH GOOD BRAKES.SOMETIMES WITH TOO GOOD OF BRAKE'S. AFTER I DRIVE IT AWHILE,THE BRAKES PEDAL WILL FELL LIKE IT HAS NO BRAKES. SOMEONE TOLD ME THAT THE BRAKE PRESSURE CONTROL VALVE WAS THE PROBLEM.I CAN'T EVEN FIND IT! MY DASHLIGHTS WENT OUT.THEY ONLY WORK WHEN I OPEN THE DOOR.THEN WHEN I TURN THE KEY,THEY GO OUT. I HAVE TO TURN ON THE FLOOR/DEFROST TO KEEP THE WINDOWS FROM FOGGING UP. THE MESSAGE CENTER DOES NOT EVEN WORK.I HAD FORD HOOK IT UP TO A DIAGNOSIS TEST, THAT COSTE $65.00. THEY WANTED ME TO TEST IT FOR THE CIRCUIT THEY FOUND FUTHER. THEY WANTED $56.00 AN HOUR.THE BRAKES ARE THE MAIN CONCERN.