No brake lights or reverse lights not working

I’ve had a the truck listed above k1500 for about 2 months. One day the brake lights went out. I have replaced everything I can think of and still can’t get them to work. Here’s a list of everything I have replaced:

Brake light switch
Fuses
Relay
Headlight switch
New tail lights and bulbs
Redid the grounds under bed

I’ve checked the plug on tail lights for power with a test light and the light green wire had no power on both sides I don’t know if that wire should I don’t know much about wiring so just asking for help before I start messing with it.