Horizon t202 treadmill makes a constant beeping with the word "connection" displayed on dash board.

https://www.treadmilldoctor.com

If you wish to get some details about treadmill repair ; check the site linked here. Pull up older posts.
http://electro-medical.blogspot.com/

you should remove the motor cover and inspect to see if you can locate where is came from. check the incline motor

if the fan still turns by hand it is likely the temp sensor or power source check if there is a fuse or review a manual for location of the sensor.

Most treadmill belt adjustments are controlled by the bolts on the back of the machine on either side of track rails. Loosen opposite side of track while running and the track will move over and tighten when in desired spot. Be care not to have it running to fast or the belt will quickly move to far over. Running for a few minutes on hire speeds after adjustments are complete to make sure belt is not in need of fine tuning.

Power board may have shorted. Check all fuses and connections. Check for loose wires. May need professional services.

follow this steps and fix it. God bless you

1.

• 1

Unplug the treadmill. Locate the console key and place the safety or reset key into the treadmill console. Replace any parts that need replacing, or is large enough to trigger with a pencil eraser or Q-tip. Plug the treadmill plug back into the wall. Use the Q-tip to press the reset button. It may be necessary to hold the reset button down for a few seconds. "CL11" will appear in the display of the treadmill.

• 3

Press the reset button one more time with the Q-tip. "CL21" should appear on the screen. Press the enter key. The display will change again and show "CL22." Keep pressing the enter key until the numbers cycle through to the number "CL26." Press enter one more time. The letter E should appear on the display screen.

• 4

Press enter twice more. The letters "SS" should appear on the screen. When this happens, press the start/stop key. Making sure to keep well away from the tread, press enter to start the treadmill. The treadmill will start on its own. The treadmill will stop on its own after a few seconds. When it stops, press the power key two times. Remove the safety key and put in a safe place. Your treadmill is reset.move on to the next step.

• 2

Locate the reset switch on the underside of the treadmill console. Usually the button

1) adjust the REED switch see the diagram attached. a) test for open 2) clean it 3) tight the connector very well and clean it

2) tight and clean it the upper and lower connectors.

3) tight and clean the ribbon cable inside from Display.

God bless you

At the end of of the running belts in the end caps will adjusting bolts you will need a allen wrench to adjust the tension. Start your treadmill and turn clockwise a 1/4 turn each time see i f you can stop the belt. You need to be aware that the drive belt can also cause this problem so I suggest that you remove the motor shroud and when you are adjusting whether the front roller is moving and the running belt has stopped or the roller has stopped and motor is rotating ( adjust Drive Belt)

Normally the button and reset is in FRONT from the machine is you stand from the machine in the lower part, Is RED and at the side is reset button.

2) Test the fuse inside see the block diagram , test and replace.

3) Test the power cord for open, break
4) test the outlet wall, reset the breaker from you house, DO not use any extension cord. and proof again.
5) If you can NOT resolve the problem, you must call to the service tech,.maybe you have problem with some component, inside capacitor, transformer in the power supply.

God bless you