Originally Posted by B and B
Not with the ECM programming I have . It is off unless I turn the exhaust brake switch on.
Same here and this what says for 2015 owners manual.
Diesel Engine Braking
This feature increases engine braking at
higher engine speeds to provide better
grade descent control with less brake and
transmission wear and tear.
Press the button located on the
switch bank next to the audio
unit to switch the system on or off
A light will illuminate in the instrument
cluster when this feature is switched on.
You can use this feature with tow/haul to
provide further increased engine braking."
My light is in the center panel just below the word "Reset" it does not come on in tow haul mode unless you press the button. You can tell the difference between it being on (light lite) and when off. I have heard they improved the exhaust brake in the 2015 models.