Its on incline 12 and wont go down. When i try to decrease it imakes sound like its happening but its not declining!!! Please help!!!!

Method 1: Press Stop and Speed Up, Insert the Key
To calibrate the incline, press and hold the stop and speed increase buttons. While holding the buttons, insert the safety key. The machine will now be in calibration mode. Press the Stop button once. Then, press one of the incline buttons to begin the calibration. It is recommended that you do not stand on the machine while the calibration is taking place.
The machine will move to its highest incline position, then to its lowest decline position. Please wait for the machine to come to a complete stop. When the machine stops moving, the calibration is complete. Remove the safety key from the console to exit calibration mode.
Method 2: Press the Stop Button, Insert the Key
To calibrate the incline, press and hold the stop button. While holding the button, insert the safety key into the console. The machine will now be in calibration mode. Press the stop button once. Then, press either the incline up or incline down button to begin the calibration. It is recommended that you do not stand on the machine while the calibration is taking place.
The machine will move to its highest incline position, then to its lowest decline position. Please wait for the machine to come to a complete stop. When the machine stops moving, the calibration is complete. Remove the safety key from the console to exit calibration mode.

You've to check the incline and decline limit switches also the incline motor
If you wish to get some details about treadmill repair and service ; check the site linked here. Pull up older posts.
http://electro-medical.blogspot.com/

The micro switch is probably bad, the button (micro switch) needs to be replaced.

I expect there is a limiter switch that tells the treadmill when it has reached its maximum elevation. The switch is probably either malfunctioning or broke.

Run the software calibration for easy diagnostic and fix it. God bless you

1)LUBE THE DECK BELT, INMEDIATELY.
2) tES THE MOTOR INPUT VOLTAGE, IF THER ARE THE MOTOR NEED REPAIR.
3) tEST THE OUTPUT VOLTAGE BOARD, FOR INPUT VOLTAGE MOTOR, IF THERE ARE NOT THE BOARD IS FAULTY.

4) tRY TO RUN THE SOFTWARE CALIBRITATION.

SINCERELY.GOD BLESS YOU

My Nordic Track Treadmill A2250 is stuck on the 12% incline position and it wont go back down and I have tried to reset it by turning it off, switching the reset button to off and then on or even unplugging it several times. What would be my next move?

Although it is fairly rare the incline motor can jam up into the highest position and get stuck there. To fix this take off the plastic hood that covers the incline motor and depending on the motor you should be able to wind it with your hand out of the highest position. When it is out of the highest position run the calibration as described in the owner's manual and it should go all the way up and all the way down. If it is not this type of motor that can be wound by hand then the first and last thing to do is to try calibration of the incline as described in your manual. If this does not work then a new incline motor is needed.

I don't know what model you have, but on some treadmills in the front there is an adjustment by a t-bit screw for calibration. You may want to try and unplug it and have someone hold the incline button while you replug it. Sometimes the program gets a glitch and a fresh restart from being unplugged corrects it. If you could list your model and brand I could be more detail specific.

Try looking here
http://www.iconservice.com/reebok/manuals.html