Today while driving my ABS & Brake light both came on. It stayed on until I shut the truck off for a little bit. I started it back up & started driving no lights, then all at once they're back on. Turn the truck off, start back driving same deal. Whats going on and what do I do to fix it. Brakes still seem good.

Speed sensor going bad most likely... Here is more information on diagnosing this problem. http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/23-brake-system/29-antilock-braking-system-abs If the speedometer is working properly then it most likely the front speed sensors going bad.

Thanks Mike, excellent write up:thumbup2:

I had the same problem and it was the rear speed sensor that was bad . It was still under warrenty so the shop fixed it so I know no more about it than that:shrug:

The only things that seem to fail...

[*]Front speed sensors

[*]Rear Speed sensor

[*]Antilock Brake Computer

So if the front speed sensors fail then the speedometer typically will work fine but requires both to be replace at once. If the rear speed sensor is bad you get a wonky speedometer that may or may not work. If the computer fails typically the ABS pump motor runs continueous...