Electrical issue
 

Intermittently of course, my blowers don't work. When this happens, the light turns on for the bilge switch. During this condition, the opposite is true, the bilge pumps won't work and the blower switch illuminates.
Sounds to me like both blowers and both bilge pumps share a ground that is marginal. Half the time, though, everything works fine. No other electrical issues with the boat. Everything on the grounding bar is tight and clean. The other grounds I could find on the bellhousing appear clean and feel tight.
Another thing is, when this condition is present, sometimes turning the key to the on position for the port motor will make everything work properly. Not always though.
Any ideas would be greatly appreciated.
As a last resort I will run new grounds for the blowers and bilges so I know where they are.
A schematic sure would be helpful.

Check behind the dash. Sounds like a ground fell off one of your switches.

I had the switch panel out, and the switch grounds are all daisy chained.