I had that problem with my 1995 silverado. it ended up being the multifunction switch. if you attempt to do it yourself my mighty careful of the air bag.
Probably the flasher unit needs to be replaced. This is an electronic switch which usually mounts underneath the dashboard.
turn signal switch needs replaced!
Yes if the wire is part of the brake lamp switch
Check the fuse
Check bulbs, fuse, bad ground, brake light switch.
Assuming the signal lights still work, no. But a bad brake light switch or a blown brake light fuse could.
in dash lights
Bulbs may be burnt out.
either dimmer switch or blown fuse If you are saying that the tail brake lights are working but the third brake light is not....It may be a defective turn signal switch in the steering column.
It needs checked out but both the hazard and brake lights go through the turn signal switch.
If the turn signal is working it's either the brake light switch or the turn signal switch.
Is the light bulb inside burnt out. If so, that would do it.