$50 Dry Wipe Fix (almost)

[TickTock]

TLDR: Works but requires a system reset to get wipers working again

Thought I would share an experiment I tried to eliminate "dry wipes" that almost worked.

The Idea was to use a 48V relay with the coil connected to the frunk power feed and the NC (Normally Closed) terminals as a breaker to the 48V going to the wiper. Then, when I was getting dry wipes, I could just turn on the power in the frunk and prevent them. No power; no wipe. Turn it off when I need the wipers back. This is what it looked like:

As expected it did throw a fault as soon as it engaged:

But I was fine with that and at first it seemed to work swimmingly. With the vehicle parked I was able to disable and reenable the wiper at will. The problem arose as soon as I tried to use it with FSD. With FSD, I *was* able to disable the wiper and continue to drive with FSD. However, I was unable to re-enable it. It appears that a wiper fault when FSD in engaged prevents any further manual wiper commands from getting sent (don't know if the auto wipe commands from FSD would succeed or not) until you reset the system (double long press on the wheel). It is unsafe to drive without a means to wipe the windshield so this is a deal-breaker for me.

My next plan is to use a microcontroller to intercept the LIN signals - then I can return the appropriate responses to avoid the fault. Having difficulty, however, finding a LIN tranceiver that operates at 48V. TI has a part for 24V systems that can work up to 48V, but my circuit needs to cover the 28-58V range of the CT system.

Thoughts? Suggestions?

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[RustyEdges]

Hey, good morning!! Ahhh @TickTock you did what? With the? And put it in where? Only to find why? Who knows where this is going to go I truly appreciate your efforts but this is where I stay on the sidelines. By all means keep us posted and stay safe.

 

[Hammy60]

Is there any reason you just wouldn’t disable the wipers from the scrub when you engage FSD? That’s what I do.

 

[TickTock]

Is there any reason you just wouldn’t disable the wipers from the scrub when you engage FSD? That’s what I do.

Doesn't work. FSD turns them back on.

 

[Hammy60]

yes. I just hit the FSD button and then the wiper off button. I save it as a shortcut on the bottom menu.

 

[pi_4x4]

every time I hit the fsd button, I hit the mic and say wipers off. It’s second nature by now…

 

[Cyber_95]

I'd settle for a fix for the wiper screeching, even when it's raining hard.

 

[Gaximus]

If you go with the LIN signal solution, instead of killing the power, just intercept the ”wipe” signal, and return a “success”. Then you could program it to ignore any “single wipe commands, but still work when holding the wipe button or setting it to anything but auto.

 

[Mikec3399]

Doesn't work. FSD turns them back on.

its so annoying, FSD turns them back on each time i engage FSD short hops around town, home cepot walmart etc, i engage, fsd, boom dry wipe
not understanding why tesla wont fix this

 

[Hammy60]

I just hit the FSD button and then the wiper off button. super simple.

 

[TickTock]

its so annoying, FSD turns them back on each time i engage FSD short hops around town, home cepot walmart etc, i engage, fsd, boom dry wipe
not understanding why tesla wont fix this

I doubt they will. They won't even let us set the max speed. They need to fix whatever algorithm they use to determine the windshield needs wiping. It seems either it isn't high priority or they are unable to. My camera feed looks crystal clear and it keeps putting me back into auto - sometimes within seconds of turning it off. Most of the time I have no problems but certain drives when the sun hits just right the only way to prevent it is to exit FSD. Since I doubt Tesla will ever give us the ability to truly turn it off I figured hardware was the only option. I was hoping someone on this forum had already been experimenting with the 48V LIN and could point me to an App Note or similar. I can always build one up from discrete components but would rather not reinvent the wheel if something already exists.

 

[Hammy60]

I just hit the FSD button and then the wiper off button. super simple. It never puts me back in auto after turning wipers off until the next FSD drive. Again, just hit FSD and then wipers off. Not sure why yours would be doing that or why you’re having so much trouble.

 

[Coaly]

Since everything you’re trying prevents powering wiper motor, what happens if you switch (remove) the ground? Does it sense if the motor actually ran?

 

[Nexus6]

Is there any reason you just wouldn’t disable the wipers from the scrub when you engage FSD? That’s what I do.

Same. Why create some Rube Goldberg contraption when you can just turn the wipers OFF when you enable FSD?

 

[TickTock]

Since everything you’re trying prevents powering wiper motor, what happens if you switch (remove) the ground? Does it sense if the motor actually ran?

I am not sure. It does expect a message back from the wiper. Whether it is just an acknowledge of the message received or if it waits to complete the wipe before indicating success I do not know at this point. Once I start sniffing the LIN I should be able to figure all that out. I am getting the fault, likely because it cannot respond without power (breaking either the 48V or the GND would prevent this).

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