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Horizon
Treadmill

Model # CST4.5 Official Horizon treadmill

Here are the diagrams and repair parts for Official Horizon CST45 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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For DIY troubleshooting advice and repair guides, visit our repair help section.

Model diagram and schematic

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ALL PARTS
Showing 10 of 128 parts  |
Controller SZTM113MCB
#M03

Treadmill assy diagram

Controller

Part #SZTM113MCB

Replaced by #032669-IF

?
Manufacturer substitution
This part replaces SZTM113MCB. Substitute parts can look different from the original.
This item is not returnable
$227.23 | 
5% OFF Phone Price : $239.23
In Stock
Socket MC0703023
#P11

Treadmill assy 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
$9.62 | 
9% OFF Phone Price : $10.62
In Stock
Breaker MC0702011
#P04

Treadmill assy diagram

Breaker

Part #MC0702011

Replaced by #003346-00

?
Manufacturer substitution
This part replaces MC0702011. Substitute parts can look different from the original.
$14.80
In Stock
Rail Lock MB0643001
#L10

Treadmill assy diagram

Rail lock

Part #MB0643001

Replaced by #001251-F

?
Manufacturer substitution
This part replaces MB0643001. Substitute parts can look different from the original.
This item is not returnable
$3.92
In Stock
Safety Key S140115001
#N33

Treadmill assy diagram

Safety key

Part #S140115001

Replaced by #016167-Z

?
Manufacturer substitution
This part replaces S140115001. Substitute parts can look different from the original.
$28.05
In Stock
Screw MZE0104203
#R04

Treadmill assy diagram

Screw

Part #MZE0104203

Replaced by #004486-00

?
Manufacturer substitution
This part replaces MZE0104203. Substitute parts can look different from the original.
This item is not returnable
$3.79
In Stock
Screw MZE0106018
#M14

Treadmill assy diagram

Screw

Part #MZE0106018

Replaced by #004590-Z

?
Manufacturer substitution
This part replaces MZE0106018. Substitute parts can look different from the original.
This item is not returnable
$2.16
In Stock
Grip Pulse MC0712021B
#N26

Treadmill assy diagram

Grip pulse

Part #MC0712021B

Replaced by #003432-B

?
Manufacturer substitution
This part replaces MC0712021B. Substitute parts can look different from the original.
$21.96 | 
21% OFF Phone Price : $27.96
In Stock
Washer MZE0502014
#H20

Treadmill assy diagram

Washer

Part #MZE0502014

Replaced by #005035-00

?
Manufacturer substitution
This part replaces MZE0502014. Substitute parts can look different from the original.
This item is not returnable
$2.47
In Stock
Screw MZE0103001
#P13

Treadmill assy diagram

Screw

Part #MZE0103001

Replaced by #004415-Z

?
Manufacturer substitution
This part replaces MZE0103001. Substitute parts can look different from the original.
This item is not returnable
$2.16
In Stock

Symptoms for treadmills

Choose a symptom to see related treadmill repairs.

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Why does my treadmill's walking belt slow down?

Main causes: damaged walking belt, improper belt tension, lack of belt lubricant, bad drive motor…

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Why is my treadmill's walking belt slipping?

Main causes: damaged walking belt, improper belt tension, bad roller bearing…

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Why is my treadmill's walking belt off center?

Main causes: rear roller out of alignment, damaged walking belt, bad roller…

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Why won't my treadmill start even though the console display works?

Main causes: missing safety key, bad control console, wiring failure, faulty motor control board, bad drive motor…

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Why is my treadmill's heart rate sensor not accurate?

Main causes: faulty sensors, wiring failure, bad control console…

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Why does my treadmill have no display?

Main causes: bad control console, wiring failure, bad motor control board…

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Why won't my treadmill power up?

Main causes: no power, bad power cord, tripped or faulty overload switch, bad power switch, wiring failure, bad motor co…

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Repair guides for treadmills

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

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How to replace a treadmill motor controller

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…

Read more
Repair difficulty
Time required
 15 minutes or less
How to replace a treadmill drive motor

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'…

Read more
Repair difficulty
Time required
 15 minutes or less
How to replace a treadmill walking board

How to replace a treadmill walking board

A worn-out walking board creates friction with the walking belt and causes the belt to slow down during use. Replace the…

Read more
Repair difficulty
Time required
 30 minutes or less

Effective articles & videos to help repair your fitness & exercise

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

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Top questions about Sears and Sears PartsDirect

Top questions about Sears and Sears PartsDirect

Get answers to frequently asked questions about Sears and Sears PartsDirect.…

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