A couple of note worthy things: If you are in cruise control and flip the easy Jake switch the cruise control will be immediately canceled. To reinstate cruise control you must first turn on back on the easy Jake switch and then hit resume on the cruise control switch. And lastly if you ever find your cruise control is NOT working first check to make sure someone has not turned the easy Jake switch off.
Did you wire them up to a t680? If so how?... i don't have a test light or an ohm meter or I would go into the clutch switch like the other guy said
I assume if you have a clutch switch on the t680 it should work. When wired to the clutch switch it just opens the switch circuit which then turns off the Jake brake and the cruise control Here’s a test you can do before any wiring. Turn your Jake on and drive down the road. Let off the fuel pedal and let the Jake engage. While the Jake is engaged push down on the clutch pedal about a third of the way. If the Jake turns off it should work for you.
Also would you have any idea where the clutch switch is on a 2015 kw t680? I looked yesterday but its not as open down there as an freightliner.