How to Start a Horizon Treadmill

1. How to Start a Horizon Treadmill: The Short Answer

Plug the treadmill into a grounded wall outlet on a dedicated circuit, turn on the ON/OFF switch next to the power cord at the front of the frame, stand on the side rails, clip the safety key to your clothing and fit it into the console, then press START for a quick start. The belt starts slowly; step on only once it is moving and raise the speed from there.

That is the "Getting Started" sequence printed, almost word for word, in Horizon’s current owner’s manuals for the T101-08, the 7.0AT-05, the 7.4AT-04 and the T202-06:

1. Check the belt. Make sure nothing is on the belt that would stop it moving.
2. Plug in and switch on. The manuals say "the ON/OFF switch is next to the power cord." Horizon’s Treadmill Guide places the power jack at the front of the machine near the stabilizer tube.
3. Stand on the side rails, not on the belt.
4. Clip the safety key to your clothing, and tug it to make sure it will not come off.
5. Insert the safety key into the safety keyhole on the console.
6. Press START for a quick start, where time, distance and calories count up from zero — or choose a user and program first, then press START.

Horizon’s help centre adds the one rule that explains most "dead" machines: "Your treadmill will not start unless the safety key is placed in position." If the console lights but shows only dashes or "SAFETY KEY OFF", the key is the first thing to check. If nothing lights at all, start with the outlet and the switch, in the order set outfurther down this page. The general version of this sequence for every brand is in our guide tohow to turn on a treadmill.

2. Before the First Start: Outlet, Circuit and Placement

Horizon’s electrical requirements are stricter than many owners expect, and getting them wrong produces exactly the symptoms people search for: a console that will not light, a belt that stops and starts, or a breaker that trips. The Treadmill Guide and the help-centre power article say:

• A grounded outlet only. The treadmill has a grounding plug; do not modify it, and "no adapter should be used." If it will not fit the outlet, Horizon says to have a proper outlet installed by a qualified electrician.
• A dedicated circuit. The Treadmill Guide says the product "must be used on a dedicated circuit," and the troubleshooting sections specify a dedicated 15-amp circuit. Its test is simple: switch that circuit off at the panel and see whether anything else loses power. If it does, move those devices to another circuit.
• No GFCI. Horizon’s troubleshooting says the treadmill should not be plugged into a GFCI-equipped outlet, or on a circuit that has one. That is the opposite of what many people assume for a basement or garage, and it is one reason Horizon also says the treadmill should not be in a garage at all.
• No power strip, surge protector or extension cord. Every Horizon document we read says the same.

Our guides totreadmill extension cordsandsurge protectorsexplain why manufacturers differ on these points; on a Horizon, follow Horizon. If you are unsure whether the outlet is grounded or the circuit is dedicated, ask an electrician to check before you rely on the machine.

Where the treadmill can go

The manuals ask for a level, stable surface, one foot of clearance in front for the power cord, at least 2 feet on each side, and a clear zone behind the treadmill at least as wide as the machine and 79 inches (2 meters) long, so you have an exit path if you slip. Horizon says the treadmill should not be in a garage, covered patio, near water or outdoors, and should not block any vents. If it has been somewhere cold or damp — in a delivery van overnight, for example — the Treadmill Guide says to let it warm to room temperature before use. Level it with the adjustable levelers under the frame before the first start; an unlevel deck makes the belt track off-center.

One rule matters for households: the Treadmill Guide says children under 14 should never use the equipment, and that pets and children under 14 should never be closer than 10 feet to it. Plan the room with that in mind.

3. Where Is the Power Switch on a Horizon Treadmill?

On the current Horizon treadmills whose manuals we read, the ON/OFF switch is at the front of the machine, next to where the power cord plugs into the frame. The parts diagrams in the T101-08 and 7.0AT-05 manuals label the "ON/OFF SWITCH" and "POWER CORD" side by side at the front of the base, not on the console. It is easy to miss because it sits close to the floor.

Horizon’s general documents hedge on this for a reason: the Treadmill Guide covers many models and says "some treadmills have a power switch, located next to the power jack" and "some treadmills have an on/off switch located behind the console." If you have an older or unusual model and there is nothing by the cord, look behind the console before assuming the machine has no switch.

The serial label is next to it

The same manuals say the serial number is on a white barcode sticker near the on/off power switch and power cord. Write it down the first time you find the switch. You need the serial number and model name for any call to Horizon, for the right manual and software, and — for a T101 — to check the2022 recall.

Does the switch light up?

On some Horizon models the switch has a red light. Horizon’s console troubleshooting starts with that light, and notes that some models do not have a lit switch at all. If yours does, it is a quick way to tell whether power is reaching the machine: a lit switch with a dark console points inside the treadmill, an unlit one points to the outlet, the breaker or the cord.

4. The Horizon Safety Key: Clip, Slot or Magnet

Every Horizon manual we read gives the safety key the same job and the same wording: the treadmill "will not start unless the safety key is placed in position," and the key "is designed to cut the power to the treadmill if you should fall." The key has a clip on a cord. The clip goes on your clothing; the key end goes on the console.

• Where it goes. The current manuals say to insert the key into the safety keyhole on the console. Horizon’s help centre also refers to magnetic keys and describes the key as "either inserted or magnetically attached," so some Horizon models, particularly older ones, use a magnet rather than a slot.
• Clip it on every time. Horizon’s warning is to never use the treadmill without the clip secured to your clothing, and to pull on the clip first to make sure it will not come off.
• Test it every two weeks. The manuals ask you to check that the key still stops the treadmill every two weeks.
• Take it out afterwards. Horizon says to remove the key when the treadmill is not in use, to prevent use by others. With children or pets in the house, keep it somewhere they cannot reach.

If the key is lost or damaged, Horizon’s help centre directs owners to its parts site, parts.horizonfitness.com, for a replacement, and links a short video on replacing the 7.0 AT key. Use the key made for your model; a generic magnet or a key from another brand may not seat or trigger the sensor the same way. Our guide to atreadmill safety key that is not workingcovers the general fault-finding.

Do not try to bypass the key. Horizon’s technician-level troubleshooting sheets describe testing the reed switch the key acts on, which is service work, not an owner fix. A treadmill that runs without a working key has lost the one control that stops the belt if you fall.

5. Quick Start, Programs and the GO Light, Model by Model

Once the key is in, every current Horizon offers two ways to begin. The quick start is the same on all of them; choosing a program differs by console. This table sets out what each manual says.

There is no separate "GO" button on these consoles. On the T101 Connect, "GO" is an LED that flashes once a program is set up, telling you the next press of START will begin it. On every model, the manuals describe START as the key that starts the workout or resumes it after a pause. On the 7.0 AT, pressing START during a workout also works as a split key and resets the segment timer.

Getting on safely once the belt moves

Horizon’s caution here is plain: do not stand on the belt while you prepare, keep your feet on the side rails as the treadmill starts, start walking only after the belt has begun to move, and "never start the treadmill at a fast running speed and attempt to jump on." Begin slowly and raise the speed in small steps with the speed keys or dial. The 7.0 AT and 7.4 AT have QuickDial scroll wheels and the T101 and T202 have speed and incline scroll wheels in 0.1 mph and 0.5% steps, plus quick keys for jumping to a set speed or incline once you are moving comfortably.

Stopping and resetting

STOP pauses or ends the workout on all four consoles, and holding STOP for 3 seconds resets the console. That reset is the first thing to try when a console seems stuck in a program or a menu, before you reach for the power switch.

A speed cap for shared homes (7.0 AT)

The 7.0AT-05 manual describes a max speed selection mode: from the home screen with the belt still, hold STOP and the chosen speed quick key together for 3 to 5 seconds until it beeps. The treadmill will then not go above that speed in any program; setting 10 as the max speed turns the cap off. It applies in miles, not kilometers. Check your own manual before relying on it, since the feature is not described in every model’s manual.

6. Starting With an App, Apple Watch or Galaxy Watch

Horizon’s consoles are not touchscreens and do not need an app to start. Every current model lists Bluetooth FTMS on its specification sheet, which lets apps such as Peloton and Zwift read the treadmill’s speed and incline, but the manuals still start the belt from the console. Turn the treadmill on and fit the key as above, connect the app or device, then press START on the treadmill.

Apple Watch and Samsung Galaxy Watch (7.0 AT)

Of the current range, Horizon lists watch tap-to-connect for the 7.0 AT only. The 7.0AT-05 manual sets out the steps:

1. Apple Watch: in the watch’s Settings, open Workout and turn on "Detect Gym Equipment." Galaxy Watch: in Settings, open Connections, then NFC, and turn NFC on.
2. Hold the watch, face toward the console, on the watch icon for about 5 seconds, until the treadmill beeps and the Bluetooth CONNECTED light comes on.
3. On an Apple Watch, choose a workout type and wait for "Start Treadmill"; a Galaxy Watch shows "Time to get started!", possibly after you accept its terms.
4. On the treadmill, select a user and set up a program, or simply press START.

For an Apple Fitness+ treadmill workout, the manual’s order is: open Fitness+, choose a treadmill workout and run or walk, hold the watch to the console, press OK on the watch, then press START on the treadmill.

Heart-rate straps versus tablets (7.0 AT)

The 7.0AT-05 manual notes that once the console is paired with a Bluetooth heart-rate monitor, it will not pair with a tablet or phone. To switch back to tablet mode, hold the Bluetooth button for 5 seconds, or reset the power. If an app will not find the treadmill, that is worth checking before anything else. Horizon’s help centre keeps a separate "How does the … connect to apps?" article for each model version.

For the T101 Connect, Horizon’s product information lists Bluetooth app sync — including Peloton, JRNY and Zwift — and the free optional atZone app. OurHorizon T101 reviewcovers its console, and ourHorizon 7.0 AT reviewcovers the 7.0 AT’s.

7. Energy Saver Mode, Sleep and a Display of Dashes

Horizon’s current information pages list "Energy Saver Mode" among the features of the T202, 7.0 AT, 7.4 AT and 7.8 AT, and the owner’s manuals refer to the treadmill going "into sleep mode." None of the manuals we read sets out how long the console waits before it sleeps or exactly what wakes it, so we will not guess at timings. What Horizon does document is the display you are most likely to see on a treadmill that looks asleep.

Horizon’s help-centre article on displays that show only dashes or 8s says: "The dashes or screen saver mode are an indicator of the safety key being off." In other words, a Horizon showing dashes is usually not broken or asleep in any deeper sense — it is waiting for the key. Reseat the key in the console (or reattach it, if yours is magnetic), and check that a magnetic key is still magnetized. Then press START.

The manuals also note that when the treadmill is turned off or goes into sleep mode, the next time it powers on it will look for the last music device it was paired with and reconnect automatically. If that device is off or out of range, the treadmill stops looking, and you re-pair from the device’s Bluetooth settings.

If the console stays dark with the key in place, it is not a sleep issue; go to the checks in the next section.

8. Horizon Treadmill Won’t Start? Work Through This Order

Horizon’s help centre and the Treadmill Guide split this into two problems, and the fix depends on which one you have.

1. The console does not light up at all

Horizon’s article "Treadmill Console Does Not Light Up" asks first whether the red light on the ON/OFF switch is lit, where your model has one. If it is not lit, Horizon lists these checks:

• Verify the outlet works — plug a lamp into it.
• Check that the breaker has not tripped, and reset it if it has.
• Confirm the treadmill is on a dedicated 15-amp circuit, not on a GFCI-equipped outlet, and not plugged into a power strip, surge protector or extension cord.
• Check the power cord is not pinched or damaged, and is plugged in properly at the outletand at the machine.
• Check the power switch is on.

If the switch light is on but the console is still dark, Horizon’s next steps involve unplugging, waiting 60 seconds and removing the motor cover to check the console cable and the wiring on the lower board. That is a job for someone comfortable working on electrical equipment, with the treadmill unplugged throughout. If that is not you, stop here and contact Horizon with the model name, serial number and proof of purchase, which its Treadmill Guide says you will be asked for. Our guides to atreadmill that won’t turn onand atreadmill console that is not workingset out the general sequence.

2. The console lights, but the treadmill will not start

• Dashes or "SAFETY KEY OFF". Reseat the key; check a magnetic key is magnetized. See the section above.
• "LUBE" or "LUBE BELT". The Treadmill Guide says the treadmill shows this after recording 150 miles and "will not operate while the message is showing." Lubricate as the manual describes, then clear it — more below.
• An error code as soon as you switch on. Horizon says this can mean a stuck key on the console overlay (see the next section).
• The console works but the belt does not move, or moves briefly. Horizon’s first check is the same power list: dedicated 15-amp circuit, no GFCI, no strip or cord. Its later checks involve the drive belt and wiring under the motor cover, which again means unplugging and, for most owners, calling Horizon. Our guide to atreadmill that turns on but the belt won’t moveexplains the likely causes.

3. It starts, then the breaker trips

Horizon’s checks for a breaker that trips during a workout are the same three: a dedicated 15-amp circuit, no extension cord or surge protector, and no GFCI outlet on the circuit. Never fit a larger breaker to stop the trips. Our guide to atreadmill that trips the breakercovers the rest.

9. Messages and Error Codes Horizon Documents

Horizon’s manuals are organised by symptom rather than by a long list of numbered codes. These are the messages its manuals and help centre explain, and what each says to do.

Two details about these. First, the stuck-key codes only appear on consoles running a minimum software version, which Horizon lists as V5.004 for the 7.0AT-04, V4.006 for the 7.4AT-04, V3.002 for the 7.8AT-04 and S4.09 for the T101-07. Second, the LUBE interval differs between documents: the current Treadmill Guide and the T101-08 manual say every 3 months or 150 miles, while the 2018 T101-05 guide said 300 miles. Follow the document for your version. The Treadmill Guide also says you can press any key to suspend the message until after your next workout, and that some older models need STOP held for 5 seconds to suspend it for 5 miles. Our guide tohow often to lubricate a treadmillexplains the job itself; Horizon’s manuals specify 100% silicone.

For E1, E2 and anything else not listed here, Horizon’s help centre is the place to look, and BarBend’s independent Horizon troubleshooting guide agrees with it on the safety-key, E1 and stuck-key messages. Our generaltreadmill troubleshooting guidecovers symptoms that are not Horizon-specific.

10. Starting an Older T101: Check the Recall First

If you are about to start a T101 that is not a new T101 Connect — a used one, an inherited one, or one that has sat in a basement for a few years — check its label before you use it.

On 27 October 2022 the US Consumer Product Safety Commission and Johnson Health Tech Trading announced the recall of Horizon T101-05 folding treadmills (recall 23-026). The CPSC’s record says the treadmills "can unexpectedly accelerate, change speed, or stop without user input, posing a fall hazard." It covers only T101-05 units whose serial numbers start with TM734 (made in China) or TM486 (made in Vietnam) — about 192,000 sold in the US, plus about 7,000 in Canada. Horizon had received at least 874 reports of the treadmills changing speed or stopping unexpectedly, including 71 reports of injury. The remedy is a free software repair delivered on a USB drive; it is not a refund or a replacement.

1. With the treadmill unplugged, find the label on the frame near the power switch.
2. Check whether it says T101-05, and whether the serial number begins TM734 or TM486.
3. If both are true and you do not know that the software repair was installed, the CPSC notice says to stop using it and contact Horizon: horizonfitness.com/support/recall, or 888-223-1045, 8 a.m. to 5 p.m. Central, Monday to Friday.

This matters for starting in particular, because an unexpected surge or stop is most dangerous when you are stepping on or are not yet settled on the belt. The current T101 Connect is a later version and is not named in the recall. OurT101 reviewsets out the recall and the software update in detail. We searched the CPSC recall database again on 18 October 2026 and found no later Horizon treadmill recall.

11. Turning a Horizon Treadmill Off

Horizon’s instruction for the end of a session is in its "Proper Usage" section: "When not in use, remove the safety key, turn the on/off switch to off and unplug the power cord." The Treadmill Guide adds that the equipment "should never be left unattended when plugged in."

1. Press STOP and let the belt come to a complete halt before stepping off.
2. Remove the safety key and put it out of reach of children.
3. Turn the ON/OFF switch off at the front of the frame.
4. Unplug the cord, as Horizon recommends whenever the treadmill is not in use, and always before cleaning, maintenance or moving it.

If you fold the treadmill, Horizon says to make sure it has come to a complete stop first, never to run it folded, and — on the T101 — to set the incline to zero before folding. Move it only folded with the lock latch secured, and never tip a folding Horizon onto its side unless you have followed the zip-tie procedure in the Treadmill Guide, because the gas shocks can spring open.

If you are still choosing a machine, ourbest Horizon treadmillscompares the current range, and ourHorizon Fitness brand guidesets out what to check before buying any of them.

12. Frequently Asked Questions