Ok, I have had this issue for as long as I have had the truck. I have an electrical issues since purchasing my 2001 Silverado. If I have the ac or heat on full blast the abs light and brake light will come on. Also, if I use my power windows the security light will flash. I’ve checked all my grounds and cleaned them. The G201 and G202 wires for instrument cluster were not mounted, so I also did that. I bought 2 new (refurbished) clusters. I also bought a brand new computer that sits right under the steering wheel inside the dash. I’m at a loss on what else could be causing the problem. I mean, it technically a classic so I really don’t need to worry about inspections, but at this point it’s just the principle of finding out WTH it is. If any idea, please for the love of god share. Forgot to mention, unfortunately a kid owned the truck before I did and I bought it from a family member, so it has been in some mud holes prior. Again, any help would be appreciated.
Tarheel77
So have you had the codes checked/read by a device/scanner that can read all the codes (not just the P codes)? OBD-II codes are categorized into four main types: P (Powertrain), B (Body), C (Chassis), and U (Network), each indicating different vehicle systems and issues. Most budget code readers only focus on the P codes.
Can't help with the "praying" thing, as I'm a definite Atheist/Agnostic....ain't gonna be any "imaginary" figures helpin' U! 
Man I wanna say thank you so much. I bought a device/scanner off Amazon, ran a test, and found out that it is most likely the abs module. It’s throwing a p061B code (pcm torque calc code)which points to the abs module. This has taken me years to figure out and I owe you one bro. Thank you so much.
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