This sounds like the accy/trip button is bad. I've read some threads on another site saying it's getting to get someone common.
OBB, thanks for your suggestion; I hadn’t considered the accessory/trip button being bad. However, I don’t necessarily agree that it is that button.
Prior to the recent upgrade, the accessory switch worked fine. Since the upgrade, the switch usually works. When it doesn’t, I proceed through the steps I listed above and it works again.
Although I’m not an IT person, like most people, I live, work and play in a world of circuitry. I’ve found that when something that previously worked fine malfunctions after an upgrade it is usually related to that recent upgrade whether it was adding new hardware, tweaking a setting, a firmware update or a new software version.
Since I didn’t save the prior software upgrade file, I cannot revert back to the previous version to check my theory, so I will have the accessory switch checked by the dealer, can’t hurt. Thanks again for the input.