Dodge Ram Odometer problems

A weird thing happened yesterday. I have a '99 Dodge Ram 1500 and the mileage is 41,372.
1. After a couple of days of none use I cranked up my truck and pulled out of the driveway an headed down the street when I noticed two lights burning on my odometer panel. A red light stated "brake" and the other an amber light which read "ABS." I checked the emergency brakes (which I never use) and saw they weren't set. I drove several more blocks down the street to see if the light would go out but no luck, although the brakes worked fine. I went back home and checked the master cylinder. It was full. I tried setting and releasing the emergency brake several times to see if something might have stuck in a particular position, but no luck. The light was still burning. If an odometer light comes on it bothers me because it's burning for a reason. One thing I thought about were the brake shoes and pads. I know they need replacing now, but I wasn't sure if there was an emergency light to tell me so. What's your opinion on this?
2. Why is the amber "ABS" light burning? What does this signify?
3. While all of the above is happening the odometer doesn't work, although the "RPM" side does. While I was driving checking the brakes I also noticed the odometer needle wouldn't move until I reached about 30mph, and then the needle was bounced to 30mph. As I increased speed to about 40mph it would hesitate a little and the needle would bounce to 45mph. When I decreased speed the needle would slowly drop until it reached 30mph then the needle would drop to 0mph all of a sudden.
The truck runs fine and the electrical seems fine. The other gauges on the odometer panel (oil, fuel, water, etc.) seem to be working okay. These two lights continue to stay on (either in the "ON" or "CRANKING" position until the engine is turned off.)
This reminds me of the TV commercial where a doctor is talking to a car and asking if it's had symptoms of coughing, sputtering, etc.
Okay Doc! What's wrong with my sick truck?

[TomKat]

Replace your RWAL speed sensor in the rear diff. It's no good.

[Dana]

Does the RWAL sensor also drive the speedometer? And serve as the vehicle speed sensor for engine control as well? I ask because I'm having the same problem (speedo shows nothing until about 40 mph and it's getting worse; used to be 20). Mine is also a 99, 4WD, manual transmission. The OBDII shows P0500 (vehicle speed sensor malfunction); the manual shows the speed sensor on the transmission (for 2WD) or transfer case (for 4WD) but according to the dealer there is no speed sensor other than the RWAL sensor on manual transmission models (which mine is).

Also, it's tending to stall when I coast to a stop... and according to the manual, the speed sensor (I thought they were talking about the transmission/tcase mounted one here) also tells the computer whether the engine's idling or doing a throttle closed decelleration. If the computer can't figure that out I could see it stalling when I coast to a stop (it idles fine after I restart it, or if I blip the gas to keep it from stalling at that point).

However, neither the ABS nor BRAKE lights are on... only the CHECK ENGINE which could also be explained by the P0138 oxygen sensor error it shows (and which could also explain the stalling problem?) I'll replace that O2 sensor when I have the money.

I don't want to simply throw random parts at it in the hopes that something will work.

-Dana

If you glue a piece of toast, butter side up, to your cat's back, and drop it from a high place, which way will it land?

[DODGEBOYS]

Vehicle Description: 1999 Dodge Dakota 3.9L, Vin X, Eng Cfg V6



Mileage: 165000



Customer Concern: ABS warning lamp is on and the speedometer is inoperative.



Tests/Procedures: 1. Check the resistance of the rear speed sensor. It should be 1500-2500 ohms.



Potential Causes: Rear speed sensor
Wiring harness
Controller Antilock Brakes (CAB)

** Confirmed Fix **
Speed Sensor in the back being replaced fixed it.