Monaco Won't Start. Batteries acting weird

Thanks so much for all the helpful advice on our Monaco that won't start. Yes, to the one poster, I did mean 16 volts, not amps. I did the check of putting the headlights on and trying to start the engine. They didn't dim, but blinked rapidly along with the blinking panel lights. Good tip also on the front/rear start switch in the engine bay but I drove it home so switch was engaged to front. I'm starting to think the engine cut off switch and coach switch for batteries were turned off when the batteries were cleaned, and perhaps the engine switch is still off. I can't reach it where its parked. Amazingly, the invertor works and generates full AC power 120 volts, 60 cycles. But generator won't start, nor will it extend from the front of the coach. It just "clicks" as well. I carefully measured volts on all the battery posts and got about 12.6 volts and also measured on the battery cables, also checked continuity on all that and fine. I'll let you know what I find out when I call the RV place tomorrow for help. Again, I always wait until I have no other answer and then post a question on RV.net, and so many great folks are quick to respond with their ideas. I sure do appreciate it.