Tesla Auto Wipers: Why They Don't Work and Why There Isn't an Easy Fix

By Karan Singh
Tesla's Auto Wipers have been a pain point for the company
Tesla's Auto Wipers have been a pain point for the company
Not a Tesla App

Tesla’s Autowipers have been a long-standing issue for customers, as well as Tesla’s engineers. Elon Musk has often mentioned that improvements to Autowipers have been around the corner for years, but they appear to have taken a rain check.

Tesla owners often complain that their wipers are running against a completely dry windshield on a sunny day, or not running at all in light rain. Moderate to heavy rain performance seems to be improved for the most recent update to Auto Wipers.

In our test, we cover the vehicle's windshield with Post-It notes to find out what the vehicle’s cameras can see.

We cover the windshield in Post-It notes
We cover the windshield in Post-It notes
Not a Tesla App

The Water Problem

Tesla vehicles lack a rain sensor. This is a result of Tesla’s strategy to rely upon Tesla Vision to replace all sensors – which they’ve successfully used most recently to replace the ultrasonic parking sensors (USS) on their vehicles. Tesla believes that vision is the solution to achieving all self-driving capabilities, and this includes the elimination of extraneous sensors such as USS and radar.

Of course, many other vehicles employ simple rain sensors that do function fairly well, and effectively detect the presence of water on the windshield. So, what’s stopping Tesla Vision from doing the same thing?

The problem isn’t Tesla’s detection methods, it’s the view of the windshield Tesla has. Water droplets are small and the three front cameras only capture a small portion of the entire windshield, making it difficult for them to capture and acknowledge the fact that there is water on the windshield that needs to be wiped away. This is in addition to the fact that the cameras are focused further away, to drive and navigate the vehicle effectively, rendering the visuals close to the camera blurry – leaving a rather technical challenge.

Our Test

The car's wide-angle camera
The car's wide-angle camera
Not a Tesla App

Even Tesla’s front-facing, wide-angle camera can barely see the yellow Post-In notes in our test, let alone the blue Post-It notes spread through the windshield. Tesla’s other front-facing camera, the “main” camera, sees only a trace of the Post-Its along the bottom. In reality, Tesla has no idea what’s on the vehicle's windshield and can only make assumptions based on a few square inches near the top of the windshield. If any rain droplets are on this portion of the windshield, they’ll also be out of focus. If the view of the rain droplets was as clear at the image at the top of this article, Tesla would have perfected auto wipers years ago.

Tesla’s third front-facing camera, the “narrow” view, is only available on hardware 3 and it’s just a zoomed-in version of the main camera, which causes it to miss our Post-It notes completely. With hardware 4, Tesla removed the narrow camera and now determines the narrow view by cropping the main camera, which has a higher resolution in hardware 4.

Water droplets on the windshield
Water droplets on the windshield
Not a Tesla App

Tesla’s Engineering Magic

Tesla is able to detect drops on the windshield when they land in front of the camera cluster, but again, since the cluster is mounted high above most of the windshield, this can lead to the windshield filling up with water droplets before a wipe is triggered.

They’ve also tried using the vehicle’s other cameras, such as the repeater or B-pillar cameras to detect falling rain – which can help the Autowiper system build confidence that there is water on the windshield. Once it has enough confidence, it triggers a wipe – or changes the wipe modes. However, in reality, due to the focal length of the cameras, it has a difficult time detecting rain droplets because they’re out of focus.
In the image below, taken from Tesla’s wide-angle camera, you can see that the water droplets from the previous image are nearly impossible to detect. On the left, is the windshield with the water droplets, and on the right is the windshield after being wiped. While the droplets cause a slightly blurry image, they’re extremely difficult to see.

How water droplets look to the camera (left) and how a clean windshield looks (right)
How water droplets look to the camera (left) and how a clean windshield looks (right)
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Wiping Away Challenges

The transition to entirely vision has left a considerable challenge for Tesla’s very capable engineering teams. The current Autopilot hardware suite lacks a good view of the windshield itself, but it can detect falling rain. Given that Tesla’s software can detect and display other vehicles using turn signals, it is also possible that they could detect other vehicles using wipers or use other cameras to see rain on the vehicle, such as the B-pillar cameras, to increase the system’s confidence that a wipe is required.

However, these solutions are likely to not be perfect, as they don’t provide an accurate representation of what the driver sees in the windshield, but instead an accurate representation of what the vehicle itself can see.

When engaging FSD on a lightly rainy day, your car may drive perfectly, but you’ll have a windshield full of rain when supervising!

Of course, there are many other reasons to run the windshield wipers beyond simple rain – spray and debris from vehicles in front, water falling from trees or being kicked up by deep puddles, or even snow settling on the windshield. Another challenge is bugs – they leave sticky smears at higher speeds when impacting the windshield, causing spots that can impede either vehicle vision or driver vision.

Future Solutions

Tesla likes to avoid solutions that only solve a single problem – such as adding a rain sensor. It is an additional manufacturing complication, adds additional cost to vehicles, and segments Tesla’s vehicles between model years.

On the other hand, cameras have solved many problems over the years – such as Tesla Vision taking over from the USS system that was present on pre-2022 Tesla vehicles. While it did take until FSD V12 for Autopark to become available to vision-only vehicles, the upgraded Vision-based Autopark is a marked improvement over the older USS solution.

Another such problem has been auto-high beams, which were solved with better oncoming vehicle detection and improved AI – which has led to a feature that is much better than its original implementation. This updated implementation has also led to improvements in the use of Matrix headlights – a feature that for now is only available in Europe and China due to legislative issues in the US.

Tesla is most likely going to be pushing another hardware revision – Hardware 5 – in the coming years. Some of the indications of this include the Cybertruck’s bumper camera – which is also expected to arrive in the Model X and Model S in the future.

There is a chance that Tesla may include a forward-facing interior at some point – to solve the fact that Vision is unable to currently see the windshield. However, Tesla also strongly believes they’ll achieve level 4 or 5 of vehicle autonomy in the future, so they could also be banking on autonomy removing the need for good auto wipers.

A Personal Example

If you get into your Tesla on a rainy day or add some drizzle via a watering jug, you can see how Tesla’s Autowipers will not activate unless water is placed directly in front of the camera cluster. You can also spray some water onto the camera housing and take a seat inside and use the camera preview to view what the cameras can see. It’ll provide you with a blurry, limited view of what the cameras see.

We may see further software improvements, but it may be a difficult engineering problem to solve with the limited camera capabilities that currently exist on hardware 3 and hardware 4 vehicles.

Tesla Smoking While Supercharging? A Look at What's Actually Happening

By Karan Singh
Hot_Engineering3140 on Reddit

Winter is here, and temperatures are dropping, so one of the most common Tesla questions is about to resurface.

If you’ve landed here after frantically searching about “smoke” coming from your Tesla while Supercharging, take a deep breath—it’s completely normal.

Tesla Smoking While Charging

If you’re Supercharging in freezing weather—even with preconditioning—you might notice steam rising from your Tesla. But rest assured, your car isn’t smoking.

Your Tesla’s heat pump is hard at work warming both the cabin and battery to keep you comfortable and ensure optimal charging temperatures. Over time, condensation and ice build-up in the heat exchanger coils.

Why Does It Happen?

When you reach a Supercharger with your vehicle, the heat pump is still running hot, but without the cold air from driving to keep the heat exchanger coils cool, the ice and condensation quickly start to evaporate—creating what looks like smoke.

Since this typically happens near the front of the vehicle, where a car would traditionally have an engine, new vehicle owners can be startled by the discovery. However, rest assured that it’s just water vapor and it’s completely normal in cold weather.

In fact, this behavior can be experienced in any EV with a heat pump in cold climates. So, if you saw steam coming out of your vehicle and panicked, don’t worry—you’re not alone.

Now that you know what’s happening, go ahead and Supercharge with confidence.

Tesla Improves YouTube App With Smoother Playback

By Karan Singh
Not a Tesla App

Tesla made a lot of improvements in the 2024 Holiday Update, including more than 15 undocumented improvements that were included in the release. One of these was a stealthy performance improvement to the YouTube app.

Several people have mentioned they’ve seen improved performance on YouTube since this year’s Holiday Update - and there’s an interesting reason why.

YouTube Improvements

The improved YouTube performance in Tesla vehicles comes from an unexpected source—Tesla actually rolled back support for YouTube’s newer AV1 video encoding. Instead, vehicles now default to the older VP9 encoding standard.

While AV1 is highly efficient in terms of bandwidth, it requires considerably more processing power to decode and display videos. VP9, on the other hand, is less computationally demanding but uses more bandwidth to achieve the same video quality. This trade-off means smoother playback and better overall performance, even if it comes at the cost of slightly higher data usage.

Intel Inside

The VP9 video codec that the YouTube app is now using is much easier to decode, making it less taxing on the vehicle’s processor. This change is particularly beneficial for Tesla vehicles with Intel processors, which previously struggled to stream video at just 720p. When using AV1, these vehicles often experienced stuttering, sometimes forcing the YouTube app to automatically downgrade playback to 480p.

With this update, Intel-based Teslas should now be able to stream at 1080p smoothly. Streaming at 1440p is also possible, although occasional stutters still occur as the system keeps up with the decoding process.

Intel-based vehicles are the big winners with this change, but this appears to affect AMD Ryzen-based infotainment units as well, providing even smoother playback.

Chromium Web App

Tesla’s Theater apps aren’t native applications; instead, they run as chromeless web apps, leveraging the open-source browser built into Teslas known as Chromium (the open-source version of Chrome). Although this works quite well, there is a severe limitation - Chromium hardware acceleration isn’t supported on Linux, the operating system Tesla uses for their OS.

As a result, Tesla vehicles rely on software decoding instead of hardware decoding, which would otherwise handle video playback far more efficiently. A potential solution could be for Tesla to transition away from Chromium-based web apps in favor of a Mozilla Firefox-based browser, as Firefox does support hardware acceleration on Linux. This switch could also open the door to better streaming performance and the possibility of expanding Tesla’s in-car entertainment options.

However, Tesla’s choice of Chromium likely stems from Digital Rights Management (DRM) requirements for streaming services like Disney+ and Netflix, which rely on DRM-enabled playback. Firefox on Linux has had inconsistent support for DRM due to codec availability and variations in operating system versions.

We’re hopeful that Tesla will either adopt Firefox or develop a fully native application to improve video streaming, rather than continuing with the current web-based Tesla Theater. This shift could also pave the way for additional in-car applications built on Tesla’s native Linux environment—perhaps even reviving the long-rumored Tesla App Store.

Regardless, this update is a welcome improvement, particularly for YouTube, which remains one of the most widely used Theater Mode apps due to its accessibility, free content, and mix of short and long-form videos. It remains to be seen whether similar improvements are made for Netflix, Disney+, or other streaming platforms.

If you’ve noticed improved performance in Theater Mode, now you know why.

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