I have a 1989 S15 pickup. 4.3 V6 auto with 270,000 miles on it. The red brake light has been on now for 2 weeks. I replaced the front pads not the problem. I had to stop real quick the other day. The truck is pulling to drivers side. I don't know if it is the caliper or brake line. Both are oem and has been on the truck from the factory. Also, I have not replaced the back brakes. I am going to check them this week end. The brake fluid is full in the master cyclinder. Don't know why the brake light is staying on.