Ok. I need you to test the switches. Take the trim panels off the steering column and locate a thin connector with a row of 6 wires in it. Below is a picture of it. C218b. Yours may have less depending on the switch options on the steering wheel. Then unplug the switch and use the meter, check the side of the connector closest to the steering wheel on pins #4 and #5. Below is the reading chart you should get when each button is pressed and held.
Speed Control Switch
Speed Control Switches Resistance Value
OFF ------ Less than 5 ohms
COAST ---285 - 315 ohms
SET -------570 - 630 ohms
RESUME----1,055 - 1,165 ohms
ON----------2,005 - 2,216 ohms
No switch pressed------4,094 - 4,526 ohms
You can do this tomorrow and let me know the results. I need to sign off because it is getting late over here and I need to go to work at my dealership in the morning.