I have a 1991 Chevy S-10 Blazer (4.3L, 4x4) in which the instrument panel lights for the Parking Brake and the Anti-Lock Braking system will not go out when the car is started. I checked the parking brake cable attached to the foot pedal to see if it was broken or disconnected but it is not. I checked the master cylinder but the fluid level is full. Brakes seem normal while driving. Any suggestions on what may be causing this or what else to try?

My ABS light stayed on in my 1994 Jeep for about 1 1/2 years before it went out on it's own. I even had a complete brake job done on both front and back brakes and it still didn't go out. There is no "trick" to making it go out - at least one that I didn't discover. I did figure out that my sensor somehow had dirt in it/on it and kept reading something that was not there and making the ABS light stay on in the dash panel. One day it went out and stayed out until I started the car the next day. Then it stayed on for a few days and then went out. It went out and stayed out for over 2 years now and I still have the proper ABS braking system that works perfectly fine. If you recently had a full brake job I wouldn't worry about a light. If you didn't have a full brake job, then I'd have the brakes looked at as there could be something more than what happened to my Jeep happen to your Blazer. P.S. the light drove me crazy the entire 1 1/2 years it was on.

If the yellow ABS light is on, the ABS has discovered a problem and turned on both lights. Generally speaking, they will stay lit until the fault is repaired or the bulb burns out.
The ABS runs a self-diagnostic test every 500 milli seconds and if it detects a fault, it will not only light both bulbs to draw your attention to the problem, but it will also store a diagnostic trouble code in the ABS module. That code will help a technician diagnose the fault more quickly.