It's one thing after another with this truck.
What does this mean and can you please give me some advice
on how to fix this.

Generally it is the abs/speed sensor in the axle.

^^^^^ +1

Mine did that and the speedo initially wouldn't work until about 10 mph, then 20, then 30 and finally 45 mph. As soon as I replaced the sensor it was back to normal. It takes about 1/2 hour and simple hand tools. Anyone who can change a tire can replace the abs/speed sensor.

That and it can cause your tranny to not wanna shift out of 1st till about 4,000 rpm.. Thats what happend with mine along with the lights and speedo issue

Same thing happened on my Durango. Dealership told me it my was ABS control module, so I paid $75 to have it rebuilt by an online service instead of buying a new one for $350.

The lights were still on after I had the module rebuilt and I did a little more research and found the sensor in the rear axle that was prone to failing. I changed it and viola the lights went out.

Just changed the ABS sensor on rear end of my sisters 3rd gen 1500. Was doing the same thing. $40 and about 20 minutes

Easy as pie, If I just recently did it, so can you! A nut and a bolt and then you can pull it. The bitch is getting the new one in with that fresh O Ring on it. Took a bit of pushing hard to get it to seat right.

I went to AutoZone and they gave me a totally different one, I had to get it from the dealer, which was about $45.

...or
if you have 4 wheel abs and your unit hub is bad, that equates to an abs+brake light problem.

That's what happened to me this past winter.

Thanks for all your suggestions.
But the speedo is fine and the tranny is shifting good.
Brake fluid is good and I still have brakes.