I have a 2014 gmc Sierra and I have left and right turn signal indicator failure. All bulbs are fine and everything works great but I keep getting this message. They will start out blinking normally then a few seconds they flash really fast and this message is displayed but all bulbs are fine. So I hooked my scanner to it and the code that keeps coming up is HVAC controls U1509-00 LIN BUS 9- Malfunction. This has been going on for months and I cannot figure out what’s wrong. I checked all bulbs, fuses and wires. All is fine. Any ideas?