1999 Chevy Truck brake lights

what do you mean you have them working but they don't come on? if they aren't coming on then they are not working properly..?

my park lights work as do my back up lights and my turn signals, but when you press the brakes nothing happens even my third light works just not my left and right side. i have replaced the stop light switch and the turn signal switch as well as the circuit board where you put the lights on. i am trying to trace the wires but caint seem to find a diagram to follow the wires off the stop light switch

Oh, ok. Well I have the wire diagram but it is extremely large so I can't post it because it would not be readable. I can post the section with the stoplight switch though.. it only has 2 wires , 1 orange and the other white. The orange wire goes to the STOP LPS fuse while the white wire runs to the CHMSL Fuse & the VEH STOP fuse. Have you checked all 3 of these fuses?

i have checked all fuses and they are good also my brake light switch has more than two wires. a orange that is hot a white the when brake is depressed powers up. a green that runs to the turn signal switch.i aint sure about the rest but i think one runs to the with that allows you to move from park to drive. the white wire i followed it up towards the fuse panel where it splits one towards the fuse and three towards the fire wall. can you send the diagram to my email to where i can see it or is therer a place to go to find exactly where the wires are going.

see if this link has what you are looking for..

https://www.2carpros.com/articles/mitchell1eautorepair-car-repair-manuals

i went there and saw the diagrams but still am lost. is there an added relayand i know that the turn signal switch allows the brake light to be lit but is there a place to get a diagram for that. like i said pior i have replaced the turn signal switch but still nothing. is it possible to run new wires and if so how is it done

if there is a relay on yours it should be labeled "Brake Lamp Relay" and located in the underhood fuse / relay center, but I believe this relay only controls the high-mount stop lamp. is your cruise control working? when the cruise module fails so do the brake lights.

well i know the fuse box under the hood is at but i dony have the lid that tells you what is what. also where would my cruise control box be located at

your cruise control module is in the left rear of the engine compartment, attached to the firewall.

ok i found it but how would this cause my brake lights to fell and if i unplug it should they work

runs though same circuit..is your cruise control working?? if it is then it is not the cause of the brake lamps.