2nd Gen Non-Engine/Transmission rear abs

[WKunkel]

my friend has got a 2001, 2500, 6-speed, with 4 wheel disc,40,000 miles.

His ABS light stays on all the time and when he hits the brakes his back tires lock up. Is there a sensor that might be bad or something?

Thanks,

Will

 

[FourBarR]

rear abs sensor on top of rear diff. left hand side ,top. there is an ohm check but i dont have my manual at home. someone will come on with it. check the plug and wiring also. hope this helps.