the other day my abs and my red brake light came on and stayed on I tried scanning it but no luck the fluid is full the emg brake is not hanging up Im not sure how to test this and is there a way to get codes or data from this my truck is a 1996 ram 2500 2 wheel drive with rwal

 

By far the most common cause is a bad sensor or connections on the rear differential.

 

Rear wheel abs sensor is toast. Sits on top of the rear diff. You can check the continuity at the ABS computer in the left hand side of the engine bay and it should check at 1800 ohms or so, I think. The sensor going **** up won't set a code....

 

What will also set a code is if you have a vacuum leak. Typically when im working in the engine bay I bump into the plug on the booster and it comes loose.
Look for vacuum leaks and check the amount of vacuum with a gauge.

 

When that happened to me, I just took the sensor out of the rear diff, cleaned it real good & replaced it & its been working fine for 100,000 miles and counting.

 

FWIW, I believe the ABS is a non OBD2 code. My mechanic tried scanning mine last week for me (I have the same issue and have had it off and on for several months). I just found out the hard way the ABS is NOT working on my truck.
He said the scanner said to ground pin 13 in the diagnostic plug and count the flashes- haven't gotten around to it yet- planning on it tomorrow.

 

The sensor housing is plastic and mine came out in pieces. I think $30-$40 is worth it to put in new plastic so it doesn't fall apart down the road....