I figured it must be the wiring so I check it against the manual and then realized that none of the wires were very secure in the terminal blocks - it didn't take much wiggling for them to come loose. I thought it must be that the extension cord I used was too thick so I made a trek to home depot and got a thinner extension cord. The terminals still won't crimp the wires tightly enough to hold them in. The slightest movement of the wires and they come out. I'm not an electrician by any stretch but wiring this controller is within my capabilities and it did work for several months. I tighten the terminals as much as I can but the wire just slips out. Each wire is about 14 or 16 gauge and is not a solid piece of copper but a strand of little copper hairs (like I said, I'm not an electrician). The extension cord is a fairly standard three prong husky brand from home depot. I am using three wire push in terminals to splice the wires together as per the diagram. It seems that I can't get the wires to stay in the terminals - anyone have any suggestions?