I have a 2003 Ram 1500 5.7L. Yesterday the ABS and Brake Light came on. By the time I got home (which was about 17 miles) there was a noise that was coming from the ABS unit. The noise continued after the truck was shut off. We unplugged the unit and it stopped. This morning I went to drive it and the speedometer doesn't work and now the check engine light is on. I took the vehicle to Auto Zone and had them read the codes. It was the speed sensor code. So I am not sure if I have to replace one of the 2 sensors and then also need to replace the ABS unit since it is continuously running. Thank you

 

I just replaced mine a few months back for the same symtoms. It was the rear axel speed sensor. It fixed the brake light & the speedometer problem.