Good Evening.

So the brake lights in my truck were working fine. I was able to connect a red wire in the back that restored brake lights (after replacing bulbs, board, brake light switch, and fuses.

Now I'm confused because I took it in to get the radiator replaced after that blew when I moved to a northern state, and had a shop replace it due to not having my tools and such accessible at the time and now my lower brake lights are no longer working.

My third tail light above the cab is working fine, but the others wont. I've also noticed that the wire I had to connect to get them working is no longer visible.

Would there be an easy fix to this? I'm thinking of taking it back to the shop tomorrow and bringing it to their attention cause I didn't think to check before I left, mostly due to brake lights not being the issue I took it in for.

 

The ground wire that is coming out of your brake light just cut it and ground it to the frame. That should work.

 

Normally a third brake light working and the bed mounted brake lights not working is a tell-tail sign of a defective turn signal switch.
The third brake light by-passes the turn signal switch.
The bed mounted lights dont as the brake light has to be canceled for the turn signal to operate.

I think your original issue was just this. Typical Chevy issue (most systems that use a single bulb for both brake and turn in the rear have a similar issue)