The ABS light on my 98.5 Ram has been coming on and off for the past year. In the winter months, it rarely comes on, and you can drive all day without it coming on. In the summer, it will come on more often, sometimes as you start the engine, or after you have been on the road for minutes to hours. Replaced the sending unit in the rear pumpkin, no change. The Dodge dealer could find no codes. I think that there is a loose wire or a short in the wire loom that effects the ABS light.
Any other thoughts?

98.5 2500 HD Ram, QC short box, Cummins AT 110,000 K
Replace lift pump at 100,000 miles.
Starter at 65 K

 

Years ago I had an ABS light on. I don't remember if it started as an intermittant light or just stedy. It was a bad wheel bearing that allowed the sensor to get rubbed bad by the disk. I checked the wheel bearings by normal wiggle method with the wheel off the ground after diagnosis and before repair and had no noticeable movement.
Brandi

 

rear sensor wire breaks internally, up near the fuel tank, right where its goes into the main harness, use your thumb and run it against the wires, if its broke internally you will find it

 

On mine, the harness was worn through at the left rear wheel where it was located too close to the parking brake cable.
It was worn all the way through the sheath of the harness and the insulation on the wires, and kept giving me a ABS trouble indication when it shorted out on the parking brake cable.

 

Just as a saftey precaution, I'd pull the abs relay until you find the bad wire.

Under some conditions, a defective ABS sensor can read as "wheels not turning" and lock out the brakes... thinking your in a skid.
I had it happen on the Interstate, approaching construction and single lane backup.
Felt like a block of wood was under the brake pedal. I ended up on the median with no damage and was very lucky but .......???

RJ