Ever since I bought my truck my abs light has been on and I'm not sure what could be the problem, I just replaced the rear brakes and its still on

 

This is the exact problem I have, the light was on when I bought it. I actually think it came on right after I test drove it. I'm at 101,000 miles,

-Changed the front brakes
-Checked fuses, guessing (ABS Pump Motor & 4WABS Module)

Could it be some wiring? Perhaps rear drum brakes (I thought these last a long time)?

Is there any considerable risk driving around with this light on? I don't notice anything different.

 

get the codes pulled...that will help you out