turn signals and reverse light wont work

any suggestions on how to fix my turn signals. checked all bulbs and replaced them. reverse light also wont work. bulb also replaced there. help plz. thx.

CHECK FUSES, RELAYS, OR IT MIGHT BE YOUR MULTIFUNCTION SWITCH

It might be your connector plate that screws to the taillight itself on the back. On my tahoe mine went out and my drivers side turn signal and brake light stopped working and made the blinker flash really fast. I tchanged all the bulds first also and still did it called the chevy dealer and thats what they told me. I found out these go out on chevy trucks after a while.