2004 4x4 silverado ABS light on

I have a couple problems ---first one is when I was driving today the ABS light came on and stays on. I changed brake pads but nothing.Bled the lines thinking could be air in the lines.... any ideas?
Second problem when I bought this truck I only have 1 brake light. (other lights work). Checked fuse and wiring but still nothing..Put in new bulb. The break light was not working before I had trouble with the ABS light staying on. Could the brake light be why the ABS light is on. Don't dare drive it for fear of having no brakes.
HELP--hope someone can give me some ideas.
thanks for any help.

I have a couple problems ---first one is when I was driving today the ABS light came on and stays on. I changed brake pads but nothing.Bled the lines thinking could be air in the lines.... any ideas?
Second problem when I bought this truck I only have 1 brake light. (other lights work). Checked fuse and wiring but still nothing..Put in new bulb. The break light was not working before I had trouble with the ABS light staying on. Could the brake light be why the ABS light is on. Don't dare drive it for fear of having no brakes.
HELP--hope someone can give me some ideas.
thanks for any help.

with the rear brake lt inop on one side,,I would check with meter if you have a voltage there...compare with side that works...if no voltage check wires to the socket...if not there check the rear junction block near rear bumper for corroded connections...

if the vehicle brakes correctly this may mean the ground for the ABS is bad,,,or possibly the fuses...

if these check out you will need to get the GM specific DTC for proper troubleshooting...then give us a response with that info...

Prob a bad wheel speed sensor.

abs problems can most of the time befixed by cleaning the hub and sencer mating serfice. one dealer told me i was using the truck all wrong. that was in 2004 when my truck was new. i had the abs kicking on and off and the light coming on. it seems chevy did not build any 4x4 for off road useage or gravle roads. when durt, mud gets in the way fo the sencer it goes nuts. my truck is a work truck and the first week i had it i was out in the woods. you should of seen the looks i was given. but clean the abs sencers up and you will be good to go. unless one has went bad.

for the light. you can bet its got the chevy grounding problem. simple test is to ground a wire to the frame then put it on the bulb. if the bulb lights you will need to clean or replace the ground wire to the bulb. chevy is bad about that. on my 85 chevy i had to run new grounds from the frame to the lights.