Humidifyer control panel,doesnt work.

Verify the humidity reading with another device. Perhaps the humidity sensor is dirty or bad.

Another possibility is the switching device that runs the compressor and fan is shorted. If it's a mechanical relay, the contacts may have welded together, or if it's a solid-state relay, it's got a punch-through or meltdown in a device junction. My guess is it's a mechanical relay since you mention it used to click on and off and now you don't hear that. The relay may be on the control board, or it may be mounted separately - I don't have a photo or diagram of the inside of your model available.

if its a newly mfg unit then yes the fans gonna run all the time , that's done to increase efficiency , if you hold down on arrows then you should be able to adjust the rooms humidity level, the default screen is the actual rooms humidity level , if you hold down mode button , this will cycle thru some timer modes that ind on the display

it should turn itself off when bucket is full , this even stops that fan from running most times

I do believe this one of those models that uses one display for both setting of humidity level and the timer , make sure you are viewing the timer function and not the humidity function , this is a very common complaint with these type as many times one sets the on time correct but then sets what they believe to be off time when they really are adjusting the humidity room level , there should be tiny lights that show function you are adjusting

If your machine is equipped with a humidistat it could be faulty and not sensing the humidity level accurately.

With the Dehumidifier switch on, pressing the Timer Button should changed between 2hr and 4hr mode.

If this is what you're doing and it isn't lighting the LED nextto the 2hr and 4hr can you confirm what setting you have for the humidity?

On the control panel the 3rd button from the left is the timer button. If you press this button when the unit is running the number display on the left will start blinking- use the up/down arrows to set the time that you want the unit to run.
If you press the timer button when the unit is off it will run on and off for the designated time you set- eg if you set 1 then every 1 hour the machine will switch on and run for 1 hour.
(The left # will just blink once you have the time you want just leave it and eventually the normal humidity setting reading will show)

SETTING THE MACHINE TO TURN ON
1. Make sure the dehumidifier is plugged in but turned off.
2. Press the button with the clock symbol below it.
3. Press the up arrow to set how many hours until you want the machine to turn ON. If you have pressed the button for more hours than you wanted then press the down arrow to lower the number of hours.
4. After you have stopped pressing the arrow buttons the display will return to the original display showing temperature and relative humidity.
5. After the above steps are completed the dehumidifier will turn ON in the number of hours that you have set (programmed).

SETTING THE MACHINE TO TURN OFF
1. Make sure the dehumidifier is plugged in and running. You should hear the fan blowing for sure.
2. Press the button with the clock symbol below it.
3. Press the up arrow to set how many hours until you want the machine to turn OFF. If you have pressed the button for more hours than you wanted then press the down arrow to lower the number of hours.
4. After you have stopped pressing the arrow buttons the display will return to the original display showing temperature and relative humidity.
5. After the above steps are completed the dehumidifier will turn OFF in the number of hours that you have set (programmed).

I don't think it's a thermistor problem, as previous respondents have suggested. I have one of these units. The control panel has been nothing but trouble. The Power button works, but the Fan Speed button is stuck on High. The Humidity Up/Down buttons only work sporadically. Sometimes they work if I keep punching them. There doesn't seem to be any rhyme or reason as to when they work and when they don't. I think they're just cheap parts that have failed prematurely.

the control board is a very simple design and it is to signal and switch options like fan speed, power on/off, humidity up/down and sets the on/off run time. Like above the board does collect dust,but the true problem runs deeper.

My unit was stuck in run mode with the fan speed, humidity and run timmer non functioning. the unit worked and the power switch turned it on and off. The display said ON

I removed the front cover (two screws) and slight pressure on the side of the cover to remove it. This exposes the control board. The control board can be removed by removing the 6 screws on the board. the cable can then be removed by pulling out the multi-pin ribbon cable.

I diagnosed that only two of the 5 push button switched were functioning. There was also dust and mold on the board. This board is poorly protected from the moist air entering the unit and the constand moisture causes corrosion on the board, the switched seem to be the weak link.

By using a multi meter I noted that only the power switch and the humidity down button were making contact when pressed. Now it all came together. I could turn it on and off. and if you press the humidity down button to the lowers setting (ON) means run all the time.

I used a elecronic contact cleaner and sprayed it into each of the switches. I wiggled it around and blew it out with canned air. It took a few wiggles and blasts but all switched then made contact. I the board back on and tested all functions and it was like new. The contact cleaner should keep it protected for a while. The non functioning of the switches works both ways. They can stick on also. This would explain most of the other control problems. These switched are common and can be picked up at Radio Shack. On a do-it-yourself bananna scale it was a 2 for me, but I had the tools and the spray. I am not sure what sears gets for the PC control board,but this is the issue and if they were to address this the unit complaints would drop greatly.

Sounds like the button may be broken. However, it could be a loose wire. Take the front off and see if any of the wires connecting the control panel and the unit are loose or disconnected.

If there is a ribbon cable connecting the control panel, see if any of the contacts are exposed when you disconnect it. If they are, you may be able to use a pencil eraser to clean them off. A service man from Sears did this on the control panel for my ceramic-top stove. He said if that didn't work then I would have to buy new control panels, which were almost the cost of a new stove!