Hi, I have just bought a 2007 Sierra 2500HD Classic Diesel. According to the manual there are 2 positions for the turn signals, first will cause the signals to flash 3 times (6 times in tow mode) for lane changes and the second position latches on for continuous flashing for making a turn.

I haven't been able to get the lane change to signal 3 / 6 times automatically, it will only flash while I hold it against the spring.

Does anyone with the classic know whether the auto lane change really is fitted?