I thought Gordon said his units didn't have those switches except one on the bathroom vent, and I presumed he was aware of the black push/pull knob. I'm glad Paul was able to assist him. It's amazing how many different versions and configurations of these vents that there are out there. Ours have 4 on-unit controls, open/close, temperature control, fan speed, and on/off, and each has 1 to 2 wall control switches. Some these days even have wireless remotes.
Gordon, look up the manufacturer's website (Fantastic Vent?) and check for a manual for your models, although determining your exact model can sometimes be a trip in itself. If the coach sits for a long period without the vents being used, the first use should be with caution; the lids have a tendency to stick to their seals with time. To avert a stripped motorized vent lid drive mechanism, the first use should involve cracking the vent open manually by pulling the black knob down and turning it slowly clockwise. Once free of the seal, the lid should open via the motor (push the knob up) without harm. Going up on the roof and cleaning the lid seal and treating it with Aerospace 303 once in a while is a good preventive maintenance practice.
Joel