You might have a bad ground either on the bcm or somewhere along the line of wires . Maybe your multi function switch. Dont buy a new switch tho they sre like 400 bucks. I know a guy in teepee that would have one. But to me it sounds like a wiring issue. Check the fuse box with a test like find all your signal fuses trailer n all and turn your right or left blinker on and touch it with the test light onnthe fuse and if smarts blinking you have a ground issue
You might have a bad ground either on the bcm or somewhere along the line of wires . Maybe your multi function switch. Dont buy a new switch tho they sre like 400 bucks. I know a guy in teepee that would have one. But to me it sounds like a wiring issue. Check the fuse box with a test like find all your signal fuses trailer n all and turn your right or left blinker on and touch it with the test light onnthe fuse and if smarts blinking you have a ground issue
Your right it has to be a bad ground I had that same problem in my 2010 chevy good luck hope u find it there great truck for the price tho
Happened on my 03 duramax and thats what i did to elimiate