turn signal problems

My problem is that the turn signals blink normally ,but when you press the brake pedal they just glow an don't blink. Now today on the way home the signals didnt even blink and when in cruise and turning on the signal cruise goes off in the morning the cruise didnt work at all. Also a few times when pressing brake pedal the radio and mileage read out would dim, but not anymore. 2001 GMC Sierra 2500 HD any help would be great. Thanks Rick They seem to be blinking ok some times and not others. Also my led light bar doesnt work right when left blinber is on the whole bar blinks and when right is on the bar doesnt work at all.

it sounds like a bad ground that is back feeding power. check the trailer light plug if you have one and light conections for damp or wet dust/mud , the brake light bulbs and turn signal bulbs the right size and working order. you may have a broken white wire on the steering column from the tilt if you have a tilt column. what year is the truck and options. 463

the problem with the light bar was the wires were broken and only the ground wire is still connected and the blinker problem I think is the turn signal multi-switch if anybody knows where I can get a resonably priced switch let me know.