Looking at the schematic, it should still set even if the resume/accel switch is open. It is normally open in all conditions unless it is depressed. All switches are inputs to the cruise module. If there are any powertrain faults stored, that can inhibit cruise operation, so check for powertrain dtc's. In addition to the stoplamp switch input to the cruise control module, there is also the ABS/TCC switch to consider.
Friday, June 17th, 2011 AT 5:56 AM