The tank is full. I was going to pull the sensor but can't quite follow the minimal Haynes instructions: which go something like:
"use needle nose pliers and pull pump and sensor out of tank. Disconnect electrical."

I don't want to pull too hard. I first disconnected the electrical plug on top. Do I just pull on the top of the unit below the plug? And if I do yank it out, what do I look for that may be keeping the light from going on? Is there a float in the tank (unlikely) or an electrical water level probe that may be bad? or??? Not a lot of room to work on pulling something out of the top of the tank. Should I disconnect the hoses and electrical from the top and then drop the tank downwards instead?

Thanks.