Remote locks stopped working replaced radio

Put the old radio back in. You fell for one of GM's many customer-unfriendly business practices. The Body Computer is built into the radio to prevent you from replacing it when it develops a problem. They want you to be tied to the dealer and their two grossly-overpriced radio repair centers.

You can also consider searching for a radio relocation kit made specifically for GM vehicles. That will allow you to cut the speaker wires and run them to your new radio, then the original radio can be mounted under the seat, (or in the trunk of cars). That will let you retain the turn signal click, chime, door locks, and other Body Computer functions.

You are in an area now that I know nothing about. For mechanics, the days of being able to modify circuits and add stuff is long gone. The insane engineers have seen fit to hang an unnecessary, unreliable computer onto every single part of our cars, and a lot of that stuff has no benefit for the car owner. There are no denying airbags and antilock brakes are worthwhile, but there is no reason to involve two computers in blowing the horn. There is no benefit to replacing a simple, reliable back-up light switch with a back-up light switch that tells a computer to turn on the back-up lights.

Rather than watch you try to resolve issues caused by aftermarket parts with more aftermarket parts, I would recommend reinstalling the original radio to be sure everything comes back to life, then use the radio relocation kit so you can keep that radio in the truck, but out of sight. You can still put the new radio in the dash.

I have never pursued this myself. The places to look are Best Buy, Crutchfield, and eBay. My first choice would be Crutchfield because they are all about home and car electronics and they have been around a long time. For Best Buy, I would stop in the store and talk with a salesman or one of their installers. Anything you can run into, they have addressed it before.