2004 cummins 6 speed the other day I installed a electric brake controler and the next day the cruse would turn on but not engague. so I unpluged the controler and still no cruse.so I checked the brake switch and lights and they worked fine and so did the clutch switch for the starter so I just fumbled around with wires and connectors and the next day cruse worked then today I moved the controler and now no cruse I did the same as before but still wont work ? help
cruse control dosn't work
Apr 11, 2006
4 Replies
You did not mention the obvious while messing with electrical compoenents.
fuses
Your best bet would be to look at the mechanical side. Not having a new diesel, I don't know how it operates on your vehicle but if it is a vacuum controlled motor, check to make sure it is still getting a vacuum on its input and if it is an electric stepper motor, make sure it is still connected.
You left out the option of there being no motor at all (vacuum, electrical, or otherwise).... because with a manual tranny, there's nothing mechanical that needs to be manipulated (no TV cable like on an automatic). All cruise control functions are handled directly by the ECM (it ignores the APPS input, and substitutes it's own fueling levels based on desired vs. observed speed), so the only thing that he could have mucked up is the brake switch sense circuit... the ECM thinks the brake is depressed, so it won't engage CC.
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