i was looking at a 91 sc with 138K on the odometer. Took it out for a test drive, and she seemed ok. But i have a few questions. 1: when braking car brakes and stops fine but the brakes red light on the dash flashes. 2: the air conditioner cycled on and off alot, and not very cold air came out. The temp said 60 and i pushed the max a/c button. it HAS been retrofited to R134a. Also the radio is the JBL and did noting but turn on or off. volume and tuner, etc didnt work. Is the head unit shot? found one on ebay $10 any help and suguestions would be appreciated