i have a 1998 12 valve dodge ram diesel. 5 speed manual .have had it since new,, 250.000 miles,, abs light is on brake light is on spedo doesn,t work. i just replace the speed sensor in the differential, that didn,t work, i replaced the cranshaft module on the front of the engine, that didn,t work, could it be the computer or power module :

 

It could be, but have you inspected your wiring all the way from the speedo sensor to the computer?