---
product_id: 372019211
title: "Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1"
brand: "chamberlain"
price: "฿2948"
currency: THB
in_stock: true
reviews_count: 8
category: "Chamberlain"
url: https://www.desertcart.co.th/products/372019211-chamberlain-820cb-replacement-garage-door-safety-sensor-2-pk-quantity
store_origin: TH
region: Thailand
---

# Instant auto-reverse on obstruction Universal Chamberlain compatibility Complete DIY install kit Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1

**Brand:** chamberlain
**Price:** ฿2948
**Availability:** ✅ In Stock

## Summary

> 🚪 Upgrade your garage safety with zero hassle and total confidence!

## Quick Answers

- **What is this?** Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1 by chamberlain
- **How much does it cost?** ฿2948 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.th](https://www.desertcart.co.th/products/372019211-chamberlain-820cb-replacement-garage-door-safety-sensor-2-pk-quantity)

## Best For

- chamberlain enthusiasts

## Why This Product

- Trusted chamberlain brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **DIY Friendly Kit:** Includes sensors, brackets, extension wire & connectors for quick, hassle-free install
- • **Safety First, Always:** Automatically reverses garage door on any obstruction to prevent accidents
- • **Long-Term Reliability:** Durable build backed by UL certification and 1-year warranty for peace of mind
- • **Sunlight-Proof Design:** Low-profile sensors reduce misalignment and resist sunlight interference
- • **Seamless Compatibility:** Works flawlessly with Chamberlain, LiftMaster & Craftsman openers since 1997

## Overview

The Chamberlain 820CB Replacement Garage Door Safety Sensor 2-Pack offers universal compatibility with all Chamberlain garage door openers made after 1997. Designed with low-profile, sunlight-resistant sensors, it ensures automatic door reversal upon obstruction, enhancing safety. The kit includes everything needed for a straightforward DIY installation, saving time and costly service calls. Certified for quality and backed by a 1-year warranty, it’s the smart upgrade for reliable, accident-free garage door operation.

## Description

The Replacement Safety Sensors project an invisible light beam across the inside of the garage door to prevent accidents and are required for safe use of all Chamberlain Garage Door Openers. Whenever there is an obstruction, the garage door will automatically reverse before causing any damage. Chamberlain compatible, these sensors replace defective or damaged sensors for every Chamberlain Garage Door Opener manufactured after 1997.

Review: Solves Problems with Sunlight - I had new garage doors installed about 3-4 years ago and they functioned perfectly (including the safety sensors) from day one. Unfortunately, we recently starting having problems with the garage doors closing in the later afternoon (North facing driveway). It was pretty clear that the sun was shining directly into the safety sensors which caused the lift motor to reverse. This was a major problem as I have a few kids who are great on their iPhones but not so great when it comes to more "complicated" home problems (i.e. running a dishwasher, washing machine, lawn mower, and garage doors). It is really frustrating to be at work and have a kid call to say they can't get the garage doors to close. It is even more frustrating to try to explain how to solve the problem to the helpless teenagers.....Enough said. Time to solve the problem. I did lots of internet research and found all kinds of hokey solutions (i.e. toilet paper roll, black plastic sun shades, etc...) but none of those seemed reliable enough to protect me from the dreaded call from the teenagers so I looked into the problem further and it appears that long-term exposure to sunlight can cause the older generation of photoelectric safety sensors to deteriorate. I decided to replace the old sensors with these hoping it would solve the problem. Good news! They did! I do have a couple of tips that might help with the install if you choose to replace your old sensors with these. First, I used a black permanent marker to mark the top location of the brackets for the old sensors. I then removed the old brackets and installed the new brackets with the new sensors as a complete assembly with the top of the new bracket at the marked line. That is much easier than installing the new bracket and then installing the new sensor (you do need to use the new bracket as the sensors are shaped differently). Next, I pre-wound some of the excess wire around a pen to create a little buffer in case I needed to move the new sensor up or down. It is only possible to do this easily if you do it before the wires from the sensor are connected to the wires from the garage door motor. I now had a buffer that would allow vertical movement if my marks were off. Finally, I cut the old sensor out one wire at a time so that I did not have to unplug the garage door motor itself. If you cut one wire at a time, you cannot create a short which might damage the garage door motor and unplugging the motor itself is an unnecessary extra step. The connectors that are included with the new sensors were perfect and easily secured with a simple pliers so all good! Once the install and electrical connections were complete, it was easy to verify the sensors were properly aligned. One sensor has an amber light and the other has a green light. It does not appear to matter how you install them. Both lights are constantly on when things are properly aligned and they flash if there is a problem so easy to verify the install. Mine turned out to be correct so I went on to test the up/down performance at the same time of day when we usually have trouble. Everything worked perfectly and I no longer have problems with the sunlight causing the garage doors to reverse! These turned out to be a simple solution to a frustrating problem. I highly recommend the kit if you are having similar problems with your garage doors auto reversing due to sunlight!
Review: Perfect replacement, saved me about $200 by replacing the sensors myself. - I was having intermittent issues with my Jackshaft Liftmaster garage door opener not being able to close. When I tried to close it, it would move a couple of inches, but it would reverse since the old safety sensors erroneously thought there was an obstruction. I contacted my garage door guy who installed it 13 years ago and he suggested replacing the safety sensors as a possible solution. This was the easiest, cheapest, and most cost-effective repair to try. My existing safety sensors did not give me any indication of failure like blinking lights. I would never have suspected that the safety sensors was the problem. These safety sensors are a little smaller than my old ones, but these worked just fine and are perfect replacements. I was able to use the existing mounting hardware, so installation was super easy. Just splice the matching-colored wires and adjust the sensors so they are aligned. All the parts that you need are included, even the wire connectors. They even provided an extra wire connector that I needed because I didn't crimp one of the connectors properly. It took me less than 45 minutes even with clean up, but I am sure others can do in 15 to 30 minutes. I took my time, since I didn't want to make any mistakes. If I called a professional to do the replacement, the sensor would have cost me $75 and the service call and labor would have been about $150 or so. Beware of unscrupulous garage door companies who want you to spend thousands of dollars on a garage door refresh (replacing all the hardware of the garage door like rollers, cables, spools, springs, etc.) and/or replacing the garage door opener itself that isn't needed. I am lucky to have an honest garage door installer that helped and saved me money. I asked him if I needed to replace any hardware and he said no, unless I just wanted to spend money. This is definitely an easy DIY project which saves you a lot of money for something that is so easy to do. I expect these sensors to be durable and last me over ten years like my old ones.

## Features

- For use with every Chamberlain garage door opener manufactured after 1997
- Enhanced troubleshooting, most intuitive safety reversing sensors
- Low profile reduces risk of being knocked out of alignment
- Whenever there is an obstruction, the garage door will automatically reverse
- Compatible with Chamberlain, LiftMaster and most Craftsman garage door openers
- Includes 2 sensors, mounting brackets, 18 inches of extension wire, instruction manual

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Brand | CHAMBERLAIN |
| Color | Black |
| Exterior Finish | Black |
| Installation Type | Screw-In |
| Material | Metal |
| Recommended Uses For Product | Preventing accidents and reversing garage doors upon obstruction |

## Product Details

- **Brand:** CHAMBERLAIN
- **Color:** Black
- **Exterior Finish:** Black
- **Installation Type:** Screw-In
- **Material:** Metal

## Images

![Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1 - Image 1](https://m.media-amazon.com/images/I/51dXnQ5v-SL.jpg)
![Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1 - Image 2](https://m.media-amazon.com/images/I/51rsOjXthHL.jpg)
![Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1 - Image 3](https://m.media-amazon.com/images/I/61vNkDmmLXL.jpg)
![Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1 - Image 4](https://m.media-amazon.com/images/I/71-bVEhCJdL.jpg)
![Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1 - Image 5](https://m.media-amazon.com/images/I/61JuHHBRq3L.jpg)

## Available Options

This product comes in different **Size, Style** options.

## Questions & Answers

**Q: remote open the door but wont close it  keep coming back up, but i can close it from the inside ,do you think this will solve the problem ?liftmast**
A: If you're able to close the door by holding down the button on the wall , then yes. However, it could be bad wiring ... maybe a bad connection. I see lots of time people use electrical tape and the adhesive actually breaks the connection over time. Try resplicing the connections if they are spliced first. If there is no splice, then it's possible the eyes are bad. To test them... use a newer 9volt battery. Detach both of the sensors and connect the matching wires together. Connect the wire with the black line to the positive side and the white to the negative. Line them so they are facing each other. If both lights come on then it's not the eyes. Could be a bad wire that is pinched or a bad circuit board on the motor unit. Good luck.

**Q: do these sensors come with wires attached to them ?**
A: 3 foot pigtails. You'll need to have wire from your opener to these and then splice them.

**Q: will they work for a craftsman opener ?**
A: Yes, I used my with a Craftsman and it worked perfect.

**Q: Could I use this sensor to light up a light when the sensor is activated?**
A: No. it has a circuit board in the door opening. It is not working like a switch but if the light is already on the garage door opener then that light will come on

## Customer Reviews

### ⭐⭐⭐⭐⭐ Solves Problems with Sunlight
*by M***N on August 4, 2023*

I had new garage doors installed about 3-4 years ago and they functioned perfectly (including the safety sensors) from day one. Unfortunately, we recently starting having problems with the garage doors closing in the later afternoon (North facing driveway). It was pretty clear that the sun was shining directly into the safety sensors which caused the lift motor to reverse. This was a major problem as I have a few kids who are great on their iPhones but not so great when it comes to more "complicated" home problems (i.e. running a dishwasher, washing machine, lawn mower, and garage doors). It is really frustrating to be at work and have a kid call to say they can't get the garage doors to close. It is even more frustrating to try to explain how to solve the problem to the helpless teenagers.....Enough said. Time to solve the problem. I did lots of internet research and found all kinds of hokey solutions (i.e. toilet paper roll, black plastic sun shades, etc...) but none of those seemed reliable enough to protect me from the dreaded call from the teenagers so I looked into the problem further and it appears that long-term exposure to sunlight can cause the older generation of photoelectric safety sensors to deteriorate. I decided to replace the old sensors with these hoping it would solve the problem. Good news! They did! I do have a couple of tips that might help with the install if you choose to replace your old sensors with these. First, I used a black permanent marker to mark the top location of the brackets for the old sensors. I then removed the old brackets and installed the new brackets with the new sensors as a complete assembly with the top of the new bracket at the marked line. That is much easier than installing the new bracket and then installing the new sensor (you do need to use the new bracket as the sensors are shaped differently). Next, I pre-wound some of the excess wire around a pen to create a little buffer in case I needed to move the new sensor up or down. It is only possible to do this easily if you do it before the wires from the sensor are connected to the wires from the garage door motor. I now had a buffer that would allow vertical movement if my marks were off. Finally, I cut the old sensor out one wire at a time so that I did not have to unplug the garage door motor itself. If you cut one wire at a time, you cannot create a short which might damage the garage door motor and unplugging the motor itself is an unnecessary extra step. The connectors that are included with the new sensors were perfect and easily secured with a simple pliers so all good! Once the install and electrical connections were complete, it was easy to verify the sensors were properly aligned. One sensor has an amber light and the other has a green light. It does not appear to matter how you install them. Both lights are constantly on when things are properly aligned and they flash if there is a problem so easy to verify the install. Mine turned out to be correct so I went on to test the up/down performance at the same time of day when we usually have trouble. Everything worked perfectly and I no longer have problems with the sunlight causing the garage doors to reverse! These turned out to be a simple solution to a frustrating problem. I highly recommend the kit if you are having similar problems with your garage doors auto reversing due to sunlight!

### ⭐⭐⭐⭐⭐ Perfect replacement, saved me about $200 by replacing the sensors myself.
*by J***W on December 2, 2025*

I was having intermittent issues with my Jackshaft Liftmaster garage door opener not being able to close. When I tried to close it, it would move a couple of inches, but it would reverse since the old safety sensors erroneously thought there was an obstruction. I contacted my garage door guy who installed it 13 years ago and he suggested replacing the safety sensors as a possible solution. This was the easiest, cheapest, and most cost-effective repair to try. My existing safety sensors did not give me any indication of failure like blinking lights. I would never have suspected that the safety sensors was the problem. These safety sensors are a little smaller than my old ones, but these worked just fine and are perfect replacements. I was able to use the existing mounting hardware, so installation was super easy. Just splice the matching-colored wires and adjust the sensors so they are aligned. All the parts that you need are included, even the wire connectors. They even provided an extra wire connector that I needed because I didn't crimp one of the connectors properly. It took me less than 45 minutes even with clean up, but I am sure others can do in 15 to 30 minutes. I took my time, since I didn't want to make any mistakes. If I called a professional to do the replacement, the sensor would have cost me $75 and the service call and labor would have been about $150 or so. Beware of unscrupulous garage door companies who want you to spend thousands of dollars on a garage door refresh (replacing all the hardware of the garage door like rollers, cables, spools, springs, etc.) and/or replacing the garage door opener itself that isn't needed. I am lucky to have an honest garage door installer that helped and saved me money. I asked him if I needed to replace any hardware and he said no, unless I just wanted to spend money. This is definitely an easy DIY project which saves you a lot of money for something that is so easy to do. I expect these sensors to be durable and last me over ten years like my old ones.

### ⭐⭐⭐⭐⭐ Eliminated Closing Problem
*by P***P on January 21, 2026*

Completely eliminated the “won’t close because it’s sunnny” problem that I had with the original sensors (installed 2019). Swapping these out was simple - great product.

## Frequently Bought Together

- Chamberlain 820CB Replacement Garage Door Safety Sensor, 2-Pk. - Quantity 1
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- 41A5034 Safety Sensor Kit, Replacement for Craftsman/Chamberlain/Liftmaster Garage Door Sensor, Compatible with Liftmaster/Chamberlain/Craftsman Garage Door openers Made After 1997

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*Product available on Desertcart Thailand*
*Store origin: TH*
*Last updated: 2026-02-23*