ABS light on sometimes

Sometimes when I start the truck, the ABS light is on and when I shut it off and restart it, it goes out and stays out? Happens about once a week.
1995 2500 4x4 by the way.

Any ideas?

does your brake light also stay on? When my brake light and abs light came on while driving after a few months my mechanic figured out my sensor was bad on top of my rear dif. It is a speed sensor that also controls your abs. Theres also another sensor that does the same thing in your transmission. I believe they are actually even the same part numbers. But I would firct check out the rear one its easy to get to. just see if the connection is good at the top. And also pull it off (it is only one bolt to pull it out) and check for a lot of metal chunks or shavings stuck to the magnet. If there is a lot try cleaning them off and seeing what happens. The sensor costs $40-$50 at your local dealer or a local parts shop like reileys or autozone or similar.

No brake light on, but I did find the rear axle seal is leaking fluid into the drums. Maybe that's part of the problem.

Jay