Horizon
Treadmill

Model #CST4 Official Horizon treadmill

Here are the diagrams and repair parts for Horizon CST4 treadmill, as well as links to manuals and error code tables, if available.

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Not all parts are shown on the diagrams—those parts are labeled NI, for “not illustrated”.

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Parts List

Showing 10 of 136 parts

Hex Wrench, 6-mm#NI

Treadmill Diagram

T-wrench

Part #MZE1002003
Replaced by #005393-00
?
Manufacturer substitution
This part replaces MZE1002003. Substitute parts can look different from the original.
In Stock
$8.50
Treadmill On/Off Switch#P02

Treadmill Diagram

Switch

Part #MC0701002
Replaced by #003326-00
?
Manufacturer substitution
This part replaces MC0701002. Substitute parts can look different from the original.
In Stock
$27.79 | 
15% OFF 
Phone Price: $32.79
Treadmill Power Cord Receptacle (replaces 003363-00, MC0703045A)#P11

Treadmill Diagram

Socket

Part #MC0703023
Replaced by #019749-A
?
Manufacturer substitution
This part replaces MC0703023. Substitute parts can look different from the original.
This item is not returnable
In Stock
$9.62 | 
9% OFF 
Phone Price: $10.62
Treadmill Power Cord#P07

Treadmill Diagram

Ac cord

Part #MC0504054A
Replaced by #002169-A
?
Manufacturer substitution
This part replaces MC0504054A. Substitute parts can look different from the original.
In Stock
$46.34 | 
10% OFF 
Was: $51.49
Wheel#L05

Treadmill Diagram

Wheel

Part #MB0103040CA
Replaced by #000037-CA
?
Manufacturer substitution
This part replaces MB0103040CA. Substitute parts can look different from the original.
This item is not returnable
In Stock
$2.26
Exercise Equipment Screw#M10

Treadmill Diagram

Screw

Part #ME0106026B
Replaced by #004595-00
?
Manufacturer substitution
This part replaces ME0106026B. Substitute parts can look different from the original.
This item is not returnable
In Stock
$2.40
Treadmill Safety Key Assembly#N24

Treadmill Diagram

Safety key

Part #S140115001
Replaced by #016167-Z
?
Manufacturer substitution
This part replaces S140115001. Substitute parts can look different from the original.
In Stock
$28.05
Membr Key#N06

Treadmill Diagram

Membr key

Part #MC0602195A
This item is not returnable
In Stock
$16.98
Screw#Q30

Treadmill Diagram

Screw

Part #MZE0107013
Replaced by #055204-A
?
Manufacturer substitution
This part replaces MZE0107013. Substitute parts can look different from the original.
This item is not returnable
In Stock
$2.16
Grip Pulse#N26

Treadmill Diagram

Grip pulse

Part #MC0712021B
Replaced by #003432-B
?
Manufacturer substitution
This part replaces MC0712021B. Substitute parts can look different from the original.
In Stock
$22.88

Symptoms for treadmills

Choose a symptom to see related treadmill repairs.

Main causes: faulty sensors, wiring failure, bad control console
Main causes: bad control console, wiring failure, bad motor control board
Main causes: damaged walking belt, improper belt tension, lack of belt lubricant, bad drive motor
Main causes: damaged walking belt, improper belt tension, bad roller bearing
Main causes: rear roller out of alignment, damaged walking belt, bad roller
Main causes: missing safety key, bad control console, wiring failure, faulty motor control board, bad drive motor
Main causes: no power, bad power cord, tripped or faulty overload switch, bad power switch, wiring failure, bad motor control board

Repair guides for treadmills

These step-by-step repair guides will help you safely fix what’s broken on your treadmill.

How to replace a treadmill motor controller

Your treadmill motor won't run with a defective motor controller. Replace the motor controller if it doesn't operate the motor correctly.

Repair difficulty
Time required
 15 minutes or less
How to replace a treadmill walking belt

A worn walking belt will begin to slow down during use. If your treadmill walking belt is worn out, replace it using these steps.

Repair difficulty
Time required
 45 minutes or less
How to replace a treadmill drive motor

A defective drive motor won't run when activated by the motor controller. Replace the treadmill drive motor if it doesn't run.

Repair difficulty
Time required
 15 minutes or less

Articles and videos common to all fitness & exercise

Use the advice and tips in these articles and videos to get the most out of your treadmill.

June 29, 2022

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