i was driving my truck to carlisle pa on sat and i looked down and the abs and brake light was on so i kept drivin because i was an hour away from home and brakes felt fine but then i looked to check my speed and its not reading. the speedometer will read once i hit sixty it goes up and down crazy any help i would greatlt appreciate thanks

 

Theres a sensor on the top of the rear axle.If this goes out,you will get the abs/brake light.Never seen it cause a problem with the speedo.I'm sure there are some other things that can cause the lights but this is the only one I know of for certain.

 

What he said. The most likely problem is that the sensor has a bunch of metallic goo built up on it and it can't read the tone ring. Pull the sensor and clean it off.

 

I just replaced one with the same symptoms you described, ABS, no speedo, ran great, The sensor is like 50 bucks from napa or dealer change it and your problems will be solved.

 

If no one has helped you, then this is what I did for my 98. It's the speed controller.
On the top inside of the rear end, you'll see wiring that is loose. This is were the speed controller is. Dodge created a stupid speed controller. The conroller is bolted into the rear end. They left the wiring exposed to the elements. If water, snow and other crap gets in there, it corrodes the wiring. You can't tell until you bend it & watch it fall apart in your hands. I bought a new speed controller. There was not difference between the old & the new. After installation, I coated the ends with dielectric grease, shrink tubed it and wrapped it with electrical tape to make sure nothing would cause any further problems.
This was 3 years ago & I haven't had a problem since.

 

thanks i going to try that and get back to you

 

thanks that was it the sensor on the rear about ten minutes and i was good to go thanks alot and the key squence does not work. but another question when i tried order the part all the sensors plugs were facing passanger side and mine was facing driver side i had to get the passangerside one because no one had one with sensor plug on the right anyone know y i couldnt find the right one i had to just cut some zip ties and pull the wire to get it to work

 

when I did mine it came wiyh an extra pig tail to extend wires

 

maybe i got the wrong part os something the lady at auto zone had two diffrent parts but only one in stock so i gust got that one plus the one was 30 that worked or the other one 100