They have separate circuits with separate fuses and separate flasher relays depending on what year the truck is.
i have conected the black and red wire to the brake and it works (the brake light that is) and i conected the blue and white to the signal lights each wire being left and right signal and it all works. but when i brake all of the light lights up the red bar for the brake and the orage bars left and right when i signal left or right whiles braking the signal works but the other signal light sticks on with the brake light. so if any one as any idears please let me know thanks
the turn signal switch is probably bad
The only thing common to all those lights (but not to the center brake light) is the hazard switch. I'd check that next. On my 96 Century the hazards override the signals and brake lights meaning that the signals and brake lights must be wired into the hazard switch somehow.
blubs blown? Check the turn signal switch.
In that case, start tracking back. The turn signal switch pulls the brake light out of circuit when the signal is operating. If the switch fails, the one or both stoplights can stop working.
Have you checked the fuses or bulbs?
your brake light switch is probably out
Power is being interrupted; the turn signal switch is a power juction see if the power is flowing thru it.
Usually this a faulty signal light switch. The Signal light switch disconects the brake light on the signaling side and makes it flash.
replace the whole light fitting
most modern cars have a bulb that share the duty.. the bulb has two filaments, one acts as the marker light, and the other works as a turn signal when activated, or as the brake light when the turn signal is not activated
it is the turn signal stalk. here is a good writup for repair. http://tss.likeabigdog.com/