My gas hot waterheater exhaust fan is not shutting off. It does shut-off if I put the switch to off... Is it a bad signal saying it should be running even though the heater isn't running or a silonoid or relay that is stuck?

Make model and year of water heater would help here. Is the flame burning when fan is running? Do you have hot water? Please let me know.

I think it's a State Select model # PR640N0VT 40 gal.. not sure the year but its 5 years old. The pilot is on and if I turn the temp up it does light off. Its just the fan won't shut off when its just a pilot on. Yes I do still have hot water.

Can you post a pic of your water heater, and more specifically where the wires from the draft inducer hook into. Im just guessing at this point, but it sounds like you may need a new control board(which on most newer side vent water heaters is built into the gas vavle, which would mean you would need a new gas vavle). Please post a pic and I will try to help further. Don't lose hope, some of these water heaters do have a sylanoid valve that can cause this problem to, much cheaper and easier to replace. Try tapping softly on any control vavles you can see, and see if fan will shut off, make sure its not calling for hot water when you do this. If you tap on a vavle and it shuts off, most likely that is the one that need replacing.

It seems to be working now. Last night I figured I would turn the heat up and get the tank hot so it wouldn't call for the burner to turn on so I could shut the fan off for awhile just in case the fan would over heat. When I went back to check it later the fan was off. I turned the heat up more just to see if it would come on and it did. Then I turned the heat back down to normal and the fan shut off OK. Then I took a hot shower so the heater would turn on again and it went through it cycle OK. I think by turning the heat up and running it through the whole cycle it allowed something to rest or get unstuck.. The day before I turned up the heat to see if it turned on OK but I turned it right back down after it did, so I never did let it go through a full cyle like I did last night. Thank you for taking the time to answer my question. =)

Just glad its working for you.. Let us know if it acts up again.