Disconnect battery for 2 minutes; however this unfortunately will not fix the problem if you have replaced the pads or rotors yoursely and the came on you may have to do more research.
In the XJ6 and earlier (don't know about later cars), there is a pressure sensor which indicates low fluid. When this sensor is bad, or there is air in the line near the sensor, the light will light up when you put your foot on the brakes. Fully bleed the brake system and re-test.
Possible that the rear sensors are broken.
There are 4 sensors on the 1995 Chevrolet Blazer. The 2 front for the Disc Brakes is behind the rotors on the hub. The inside hub has gears and the sensors are above them. On the rear, where you have Drum Brakes, the sensors are on the back of the Drum Brake Assembly, next to the bleeder screws.
abs sensor
get your rotors turned. If it's the ABS turning on or off you might need a new sensor for the wheel. The S-10 ABS had a design flaw and the ABS sensors on the wheel sometimes break.
Could be a speed sensor - have vehicle scanned to determine the problem
The Colorado 2.8 crankshaft sensor and camshaft sensor work in harmony to control the spark or fuel delivery and timing. These two consist of tone and ring which passes over a magnetic sensor.
The sensor for the rear wheels are located on the brake shoe backing plate if you have drum brakes on the rear. The front brake sensor is located next to the caliper. The same if you have rear disc brakes.
check crankshaft sensor sensor
They are behind the front rotors and you can't see them. But you can see were the electric wire goes in behind the rotors that hook to them.
2007 Colorado will have a knock sensor which adjusts the timing automatically.
It is built into the mass air flow sensor.