My ABS light stays on all the time, I just dropped it off a couple hrs ago at a heavy duty truck service center to get it checked , just received a call they could not get a connection I don't know if...
When was the last time your brakes were adjusted? Even with auto slack adjusters, which you should have, you have to check them. An out of adjustment slack adjuster can also trigger the ABS light. I have had it happen to me.