Hey i got a 99 D 5.9 & the Break light and the abs light never turned off when i started it up this morning. After i pulled outI noticed that the speed tack was staying at 0mph untillI hit 30. I figured it was a fuse or somethingsoi checkedeverything and there was no bad fuses. any ideas on whats going on?

 

It's the rear speed sensor. I have personally never had the problem but it is one of the things that go out on the D's more often. It is a straightforward fix.

 

Hey,
i have a 99 Durango 5.2L that has the same problem. I would really like to know more about this speed sensor if anyone has any info. I have also dicovered that my proportional valve is stuck and im not getting any fluid to the back brakes. Where is the speed sencer mounted so i can replace it?

 

If the speed sensor is the problem, it is the sensor located on the rear dif. See your service manual for removal/installation.