Horizon
Treadmill

Model #4.2T Official Horizon treadmill

Here are the diagrams and repair parts for Horizon 42T treadmill, as well as links to manuals and error code tables, if available.

There are a couple of ways to find the part or diagram you need:

  • Click a diagram to see the parts shown on that diagram.
  • In the search box below, enter all or part of the part number or the part’s name.

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

We encourage you to save the model to your profile, so it’s easy to access parts and manuals for your appliance whenever you log in.

For DIY troubleshooting advice and repair guides, visit our repair help section.

Showing 10 of 145 parts

Treadmill Walking Belt Lubricant (replaces 016591-Z, DC200-1000CS, MB1102001A)#NI

Treadmill assy Diagram

Bottle set

Part #MF0821002A
Replaced by #1000092805
?
Manufacturer substitution
This part replaces MF0821002A. Substitute parts can look different from the original.
This item is not returnable
In Stock
$17.79 | 
10% OFF 
Phone Price: $19.79
Treadmill Power Cord Receptacle (replaces 003363-00, MC0703045A)#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
In Stock
$9.62 | 
9% OFF 
Phone Price: $10.62
Treadmill Rear Roller#AR2

Treadmill assy Diagram

Rear roller

Part #SM0908015A
Replaced by #014682-B
?
Manufacturer substitution
This part replaces SM0908015A. Substitute parts can look different from the original.
In Stock
$119.99
Treadmill Console Cable#P06

Treadmill assy Diagram

Console cable

Part #MC0502044A
Replaced by #002103-A
?
Manufacturer substitution
This part replaces MC0502044A. Substitute parts can look different from the original.
In Stock
$25.94
Treadmill Power Cord#P16

Treadmill assy 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
Treadmill On/Off Switch#P02

Treadmill assy 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
Exercise Equipment Bolt#H30

Treadmill assy Diagram

Bolt

Part #MJ3022016A
Replaced by #008629-A
?
Manufacturer substitution
This part replaces MJ3022016A. Substitute parts can look different from the original.
This item is not returnable
In Stock
$2.16
Treadmill Screw#P17

Treadmill assy Diagram

Screw

Part #ME0102042
Replaced by #004381-00
?
Manufacturer substitution
This part replaces ME0102042. Substitute parts can look different from the original.
This item is not returnable
In Stock
$2.16
End Cap#Q07

Treadmill assy Diagram

End cap

Part #MB0238002DB
Replaced by #000386-DB
?
Manufacturer substitution
This part replaces MB0238002DB. Substitute parts can look different from the original.
In Stock
$8.15
Exercise Equipment Washer

See All Related Diagrams

Washer

Part #MZE0505033
Replaced by #005196-00
?
Manufacturer substitution
This part replaces MZE0505033. Substitute parts can look different from the original.
This item is not returnable
In Stock
$2.26

Symptoms for treadmills

Choose a symptom to see related treadmill repairs.

Main causes: faulty sensors, wiring failure, bad control console
Main causes: no power, bad power cord, tripped or faulty overload switch, bad power switch, wiring failure, bad motor control board
Main causes: missing safety key, bad control console, wiring failure, faulty motor control board, bad drive motor
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

Repair guides for treadmills

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

June 1, 2015
By Lyle Weischwill
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
June 1, 2015
By Lyle Weischwill
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

Top questions about Sears and Sears PartsDirect

By Lyle Weischwill

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