Make sure the on/off switch is in the on position. It is located close to where the electrical cord goes into the unit. If it is in the on position and the key is in place do the following:
first thing is check for any loose connections or bad wiring and then follow the steps below to try and determine what is wrong with your treadmill.

* Make sure the safety key is inserted or mounted securely on the console.

* Check the breaker on your treadmill it can be combined with the on/off switch or it can be a separate breaker. Make sure it is not open.

* If that tests ok, check to see if your getting power to the motor controller(electronic board under the hood) this can be done by following the power cord in and testing where they attach, if you are getting 120/240 volts then check the light(s) on the controller If they are not lit then the controller is bad.

* If they are lit you will need to check the dc voltage going to the motor

* Also make sure you have voltage going to the console
if you have 8-12 vdc voltage to the console and the console is dead replace the upper control board.

* If only one or none of these voltages are present then the controller is bad.

* If your treadmill is equipped with a separate power board then you will need to take voltage readings going in and coming out from the board If nothing is present then the power board is bad. If all tests well move on to the controller.

* some motor controllers are equipped with a fuse on it, if this is blown the console will not light as well.

* Hopefully it is just a breaker.

* Make sure you are lubricating your treadmill as well on a regular basis. Too much friction can wear out electronic parts and reduce the life of your treadmill. Use the appropriate lubricant recommended for your specific model and never use an extension cord.

Thank you for the question and please feel free to contact me again with any questions or problems you may have.