Turn the ignition key to accessory position set the odometer to odometer (not trip), turn the ignition key to the run position while holding down the odometer button, for over five seconds, odometer will read "000000" and then the light goes out.
Patrick, thanks for the info. Our mechanic keeps telling how to do it and of course when he does it's as easy as opening the window! So easy that we're embarrassed to keep asking how. But now we have it in writing! Thanks to you and WayneT for asking the question!