The auto stoped working on my live well, it works just fine in manual. Any ideas where I should start to look into this trouble? The switch or the pump itself? Where is the timer that decides when to turn on and off?

Great site thanks to all for so much help.

I will miss Ben and all his knowledge (but that is another post alltogether)

I'm just guessing but, I think that would be a "relay timer switch" other than a "pump" issue. If your pump works on manual then that would tell you it is a switch issue. Your switch position controls when the power is sent to the pump. "Manual" constant voltage to the pump, "Auto" power to the pump for a certain amount of time, time delay relay shuts it off for a certain amount of time, then back on, then off.... you get the picture. Not sure if the time delay realy is part of the switch or not.  Look at your other switches to compare if that switch is a bigger with more components or pull the switch and take it over to a local electronics wholesaler. They should be able to tell you if it is a TDR switch or not and more than likely have it in stock.

Good luck