Hello and welcome to JustAnswer!
Does your speedometer ever act up?
Does the abs try to activate when you are at the very end of a stop?
Do you have the two wheel or four wheel system?
If the speedometer works ok we should be able to rule out the rear speed sensor and it's wiring. That leaves the front sensors, wiring, the module, and hydraulic control unit. The first thing you'll want to do is check the fluid level. If there is a leak in the system it will cause a pressure drop, and turn the lights on. If the fluid is ok, you'll have to start by getting the codes read from the ABS module. Older models had a flash code method for the ABS, but your truck doesn't support it, so the codes have to be read with a scan tool or special ABS code reader. This is something you can go to a shop for, but it might not hurt to try a parts store first. Many times they check engine codes for free. ABS code readers are starting to become common now, if you've got a large parts store they may very well be able to get you the ABS codes. If you can get them and let me know what they are I'll glad help you get the truck fixed, but at this point unfortunately I can only tell you a couple things we can rule out, rather than an exact fix. There are 42 different codes that can be set, so that leave alot that it could be.
This is not an incomplete answer. I'll gladly help you come to a conclusion on your problem, but guesswork isn't my thing. There are entirely too many different things that could be wrong with your truck for me to tell you something that I think it may be. If I told you something that it probably was and you went out and spent $400 or a repair and it didn't fix it, you would have rather I told you to get the codes read first so we can actually figure the problem out. There is no way for me to tell you exactly what is wrong with it without knowing what codes are stored.
You don't use a laptop to read abs codes. There are abs code readers out there that plug into the data link connector just like an engine code reader. Almost all parts stores will read engine codes, I think it would be worth a shot to try and have the codes read for free before taking it to a shop.
You don't have to pay if you aren't satisified with an answer. I am not paid regardless if you are satisfied or not. You haven't spent any money yet, and I haven't gotten paid. You don't release any money from your JustAnswer account until you click the green accept button. I don't expect you to accept until we got your truck figured out, and I didn't expect yesterday's correspondence to be the end of our dealings. If you get the codes read, we'll get your problem figured out. But electrical problems are way to broad to be able to give you a for sure fix without doing some diagnostics.