Brake Abs Warning Light problems of the 1998 Oldsmobile Bravada

I have had numerous problems with my 1998 olds Bravada. First the blinker sound won't shut off. When the ac is on for more than 25 minutes the motor gets really loud and the speedometer needle starts jumping. Finally my brakes get sticky when it's hot outside then the abs light comes on and it feels as if the brakes aren't going to engage and the speedometer needle starts going crazy again. This is something that shuts off and starts all over again every time I start the vehicle.