Headlights work, brake lights and turn signals work but rear running lights don’t work, what’s the issue? I have replaced all bulbs and checked fuses.
Check the wiring especially the ground wire and pray it's not a bad module like the body control module that costs a ton
You need a test to confirm you have 12v voltage in your running lite socket or not on the back end of truck. if there is no voltage then you need to check the other side as well. Then make sure the running lite fuse is good to be sure. If fuse is good then the problem lies in between..broken wire or connector to the back of truck.
If you do have voltage and you insert the bulb in which is good and still no light then suspect you lost the ground connection. That ground connection can be close by connecting to the body
Additional info
Black is ground
Yellow is left signal
Green is right signal
Brown is running lights
If you are having problems with the tail lights check the wiring harness blocks for corrosion or rust. You may just need to replace them, If so make sure to lubricate well with Vaseline, this minimizes the problem with it later
You don't by chance have a trailer wiring harness spliced into the main wiring harness. If you do, start there, looking for corroded or broken wires.
