That is my thought , it just flashes the ABS light only, continually as soon as you turn on the ignition. Used is my only source , fingers crossed I can find a good one .

There are many on ebay , the problem is unless I can find one from a truck like the truck i have , dana 70 and 245 65 16 tires , i need to reprogram it .

thanks for everyones help so far.

Abs ecu is bad common problem in those trucks.

I believe this is the case , I learned more about how the system interacts with the PCM accidently .

Yesterday while trying to trouble shoot it I pulled out the CAB and tried to open it up , which was unsuccessful. I gave up tryingto open it without damaging it and just tossed it on the front seat of the truck and cleaned up to go out to dinner. This morning I went out in the truck and noticed the ABS light was still on , same as if the fuses were pulled , but this time the brake warning light was also on , it's never been on other than during the cluster self check, but I suddenly noticed that the speedo was not reading , what the ?? I did pull the rear end sensor to check for debris or damage but I never unplugged it , once I got to a safe place to stop I reinstalled the CAB unit , the speedo is now working again and the abs light and the brake light are on solid, I did not reconnect the solenoid unit. when I got to where I was going I reconnected the solenoid unit and the brake light went off and the abs light was once again flashing. This is telling me the solenoid is good and the CAB is the problem.

Now to find another cab and hopefully not have to pay a dealer 152 dollars to reset the rear end and tire size codes .

Does the truck have a posi rear?

limited slip ... yes

I never updated this , I was able to find a used one local off a 1500 4x4 , the speedo read wrong, as I expected, and the ABS light went from flashing to being on along with the brake light . It gave me codes saying the solenoids were an issue but no code for a bad power relay so I was headed in the right direction. I I drove it like that for a short time then decided to put the original back so my mileage count was at least correct.

Eventually I found a same part number CAB and sol pack on ebay so I bought it ... problem solved ... sort of, sometimes the ABS and brake warning light stays on after the self check cycles , both before starting and after . I figured out that if I pump the brake pedal a few times right after I start it will turn the lights off after the 2nd self check, but not always , but it's good enough that the sometimes I only get one rear wheel to lock in a panic stop and I can get my annual safety inspection sticker. I have yet to swap in the sol pack that came with the new CAB .

Make sure the rear wheel ABS sensor is a Chrysler sensor.

I had a steady ABS on light on a '99 1500. I just swapped it with an OEM new sensor and the light went off right away.

I cracked the old sensor open to satisfy my curiosity of what's inside: plenty of tiny wire in there.......I think enough that if your rear diff fluid is dirty, over time, some of that stuff might just clog some milivolts from happening in the sensor.

Just a theory, but maybe dirty rear diff oil can foul the sensor.....like any other sensor can be affected by contamination: O2, IAT, etc....

I got one from a closed dealer, I wanted one for ages when the first steps for most of the service manuals is to connect a DRB.