i currently have no brake lights. My back up lights and running lights work. ive checked all my fuses replace the bulbs. ive replaced my brake light swicth and also my tail lamp circuit board. ive have not lost ground to my brake light sockets but not getting 12volts.
See if the hazard flashers work.
If not, the problem is most likely with the multi-function switch in the steering column.
The current path from what I can guess starts at the battery, through a 25 amp stop lamp fuse, connector c202, 15 amp vehicle stop fuse, connectors e7 and c3, rear lamps junction block, then to the stop lamps themselves.
Edit; there’s also a separate 10 amp fuse for the high center stop lamp it appears, named “vhl chmsl” fuse for some reason.
vhl = “vehicle”
chmsl = Center High Mounted Stop Lamp
Sounds like the classic signs of a bad multi-function switch.
Usually the middle brake light is tied directly to the brake switch so if that light works it indicates the brake switch is doing its’ job and power is good past the switch. As was mentioned the most likely culprit is the multifunction switch or the emergency flasher switch if that is a separate switch. Try cycling the switches a number of times to see if that clears the trouble.
Chances are the above replies are pointing you in the right direction. Be aware of one other possibility. When this happened on my 2001 Silverado, there was a corroded connection in the junction box under the rear of the truck, behind the spare tire. Your model year is not that far off from mine, so there may still be this junction box. From the junction box, the left and right rear light harnesses plug in to the box and branch off to each side. I had to replace the box and the harness.
If this is the cause, when you fix it put dielectric grease on the connections to prevent future corrosion.