Chamberlain’s Second Generation of IR Safety Sensors
Model/part number 041A5034 (1998-2022)
The second version of safety sensors from LiftMaster and Chamberlain, technically called part number 041A5034 (or 5034 for short), was released in 1998. These are the most common safety sensors we see out in the field, and also the most annoying. I have been on more service calls for this particular model than any other (probably all others combined), and it is almost always an alignment issue. Unfortunately, there are multiple design flaws that can compound to make troubleshooting and re-aligning this specific model a real headache.
The build quality on these sensors is solid, but there are big problems with the design of the 041A5034 safety sensors:
- Unbelievably bad and complex bracket design that is the root cause of most of the other issues. I will have a separate post on how to mount the safety sensor bracket so it never comes loose.
- The wingnut that tightens the sensor down is prone to coming loose on its own from vibration and years of temperature cycles.
- You can break the spot where the bolt for the wingnut slides into the sensor in which case you will have to tape it to the bracket.
- Indicator lights are too small and dim, hard to see in bright sunlight.
- The little light on the receiving eye only turns on when there is both power to it AND it is receiving a signal from the sender. This means you can’t tell if you have a problem with alignment, the wiring, the circuit board, or the sensor itself. Tracking down the source of the problem is multiple times more complicated than with any other common brand.
- Sensors are “polar” so there is only one way that wiring from the sensors can connect to the circuit board. This doubles the options you have to try if you don’t know which wire is which, making troubleshooting even harder, especially on certain wiring schemes.
To summarize the issue, it is easy for the Chamberlain 5034 sensors to come out of alignment for a variety of reasons, and the indicator lights don’t give you enough information. This is where you can get stuck, chasing the wrong problem.
Look Closely
The green indicator light on the receiving sensor can be downright deceptive.
When the connection is completely broken, it will go out. But, if the sensors are ALMOST lined up, it will flicker so slightly that many people think that it is actually on, essentially a “false positive”.
When the connection is low quality like this you will get unpredictable failure to close which is incredibly annoying (this is how many people accidentally leave their garage doors open all day when they go to work). It could act up seemingly at random, or for weeks at a time then not again for months. Tiny movements caused by temperature changes, vibration, etc can cause the proper connection between the sensors to come and go.
The best way to tell if the green light is truly on is to darken your garage and then look at the sensor from as close as possible. I have been to many hundreds of service calls where at first glance the sensors seemed to be lined up, but in reality the green light was flickering and the connection was not good enough to allow the door to close consistently.
If there is any flickering at all your garage door will act up. Here’s a video of a sensor that looks like its on but really has flickering green light.
Did you see that? Its very subtle (most obvious right at the beginning) but that tiny bit of flickering is all it takes to cause your door to reverse.
If this is one of those times when your door seems to be closing like normal, gently wiggle the receiving sensor as the door is closing. If a tiny bit of movement causes a reversal you have found your problem.
This problem is made worse when the mounting brackets are attached to the track (about 90% of installations thanks to the clip-on design) because any wiggling or vibration can cause the connection between the sensors to be broken. While this can happen with any brand, the combination of dim indicator lights that go out rather than flash, a track mounted bracket, and safety sensors that come loose on their own makes it especially common and confusing with Chamberlain products.
Here are few common symptoms of *almost* lined up safety eyes that homeowners and inexperienced garage door technicians often get tripped up by.
- Garage door refuses to close sporadically.
- It may work like normal for weeks or months without any problem then acts up for a few days. Or it could happen all the time, closing successfully just frequently enough to give you hope that it has fixed itself.
- You have trouble getting the door to close when there is sunlight shining on one of the sensors.
- Garage door reverses at random points.
- This can be confused with a worn-out part causing the door to bind, a bad circuit board or other electrical issue with the motor, worn gear, or any number of things.
- Your garage door reverses when it is near the ground, at pretty much the same spot every time.
- On lots of garage doors the bottom of the vertical track wiggles a little bit as the door closes. If the safety sensors are mounted to the track (as they almost always are with Chamberlain openers), this small amount of movement can be enough to break the connection if the eyes aren’t very well lined up in the first place. Also check to make sure there is nothing hanging from the bottom of the door, for example a spider web with a leaf stuck in it.
- You come home and your garage door is open.
- There is a good chance that the safety sensors caused the door to reverse right before it hit the ground — but you were already driving away. That being said, it could be “phantom operation” or some other problem with the door. But it is much more common for a garage door to reverse before it was done closing than to open on its own for no reason.
Beware: there is a common garage door scam in which a dishonest technician pretends uses this scenario to convince the unsuspecting customer that there is an expensive problem with the circuit board.
Remember, if you have a LiftMaster or other Chamberlain manufactured garage door opener from pre-2022 and the lamp on the motor flashes 10 times after it reverses to the top it is DEFINITELY A PROBLEM WITH THE SAFETY SENSORS!
If the lightbulb is either burned out or missing, you will hear 10 clicking sounds coming from the motor.
If you do not get this error code it is definitely NOT a problem with the sensors.
How to Line Up LiftMaster and Chamberlain Safety Sensors
Check out my guide to lining up your safety sensors for the best procedure to follow, regardless of brand. Beyond that, there are a couple of other details to know about LiftMaster and Chamberlain safety sensors.
Make sure that the bracket is fully snapped onto the track. They get knocked loose frequently which makes them aim in a funny direction.
Don’t worry if the sensors don’t seem to be sitting perfectly straight in their brackets. All that matters is that it is aimed at the sending eye and the wingnut is tight (it should of course also be UL-325 compliant). Because they are made to snap onto the track, which is by no means guaranteed to be perfectly straight, it is common for the sensors to be aimed on a funny looking angle compared to the geometry of the bracket.
If you can’t get the wingnut to tighten down you can use some electrical tape to help hold the sensor to the bracket. Be sure not to cover the indicator light with tape.
It is ideal to bolt the bracket to the track using a 1/4″ track bolt and nut with 7/16″ head.
Do my “flex test” to check the quality of the connection.
The root cause of misaligned LiftMaster and Chamberlain safety eyes is usually a poorly installed mounting bracket. I have many more tricks and details you can you use to make your sensors as solid as possible in my guide to mounting LiftMaster brackets.
And if you have done all of the troubleshooting steps and it is simply impossible to ever get your door to close with one click of the button, it could mean one of your sensors has gone bad (although you should double check any wiring connections). It could be either one, there is no way to tell other than process of elimination but its best to just replace the pair to be safe (you have to buy them as a pair anyway).
The LiftMaster/Chamberlain 041A5034 is no longer made but should still be widely available online. However, I recommend using the current model # 041-0136 instead. They are compatible with your existing brackets and have much better indicator lights.
