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LED Headlight RetroFit on Older Cars

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Right off the bat I noticed that while the plugs for the old light and the new were identical, the new light had pins where the old harness didn't and the old harness has pins where the new light doesn't. No bueno.

So I took it apart and tried to trace wires but I would have needed to bake the assembly apart to really see where things go. Thanks to this post I had the confidence after two hours to at least plug it in and see what it did without the fear that I would melt it because even though pins had changed, I wouldn't be plugging a ground in where a ground didn't belong or a 12V where that didn't belong.

Here's what I got...

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From the pinout I knew that my turn signals would work. They did...

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So the good news: No errors displayed. Low beams and turn signals work. This means that as it sits, I can install it and it will work just fine for it's basic purposes. Yay!

The bad news: High beams and DRLs do not work. I'm crossing my fingers that these are not CAN controlled or if they are, they're controlled the same way as the classic headlights. If they aren't then I'll likely need to break the DRLs off onto their own circuit and control them some other way but I still have pins in the new headlights that don't have anything going to them so I'm pretty confident right now that if I can find the right combo, I can move pins in the old cable and get highs.

What I'm unsure of: These are the adaptive lights. I am unclear if the stock classic headlights receive a signal for wheel position. If they do not then I'm not sure how I would implement this. As it sits all of the lower row LEDs are lit.

Stay tuned for more!
 
A little update. It appears that the pin the old headlights use for low beam is the pin the facelift headlights use for constant power. Because if I turn the headlights off I also lose the fan in them as well as the turn signal. So that's a fun development.

The turn signal also blinks really fast with the new light plugged in which is peculiar because both the old and new lights use LEDs for the turn signal.

That said, I have a 12V source on my harness that's not going anywhere on the new headlight. So I'm far from having this properly hooked up. Anyone with a copy of the pinout for the facelift headlights? That would really put this to bed for me. I can swap wires in the harness but right now I'm really guessing. I don't want to pay for access to the online manual only to discover that the new headlights aren't in there yet.

So if anyone has access to that I would be forever indebted.
 
Alternatively, if anyone has an extra headlight harness end hanging around that might just work. Otherwise I'm going to pop the plug off of this guy and run a pinout on the existing wires but that doesn't sound even a tiny bit fun so I'd like to avoid of possible.
 
I made a breakout box because I'm impatient. Unfortunately I'm nearly certain the new lights are using the CAN bus for a lot more functions than the older HID lights which makes any kind of easy retrofit pretty much impossible. I can not seem to enable high beams or the DRLs and I suspect the reason for that is because they don't use the harness directly like the old headlight but instead rely on CAN data.

There is one less pin on the new lights; two less pins if you consider that the new lights have two ground pins and the old lights have one. You can get them on and working in their most basic fashion but if you cut power to the low beams that cuts power to the turn signals and then it's game over. And you still wouldn't have high beams or DRLs.

My service advisor seemed to think Tesla was going to offer a retrofit kit for these but we didn't go too far down that road. If they offered a new headlight harness that tapped into the bus and then coded the car to let it know it had these lights, I could see that being rather easy. BMW used to do that and I think they still do in fact. Tesla also does it with other equipment like the Continental TPMS upgrade, folding mirrors, parking sensors, etc.

If someone else has access to the pinout on the facelift lights I'd appreciate it. More or less to satisfy my own curiosity.
 
No assistance on the pin out, but I'm curious, does the "toy car" on your IC show the headlights on? I have aftermarket LED retrofit lamps installed, to replace original halogens, and the IC shows the lights off all the time. As if they've been burned out. I assume it measures lamp resistance (or something else?), which must be much smaller for the LED.
 
A little update. It appears that the pin the old headlights use for low beam is the pin the facelift headlights use for constant power. Because if I turn the headlights off I also lose the fan in them as well as the turn signal. So that's a fun development.

The turn signal also blinks really fast with the new light plugged in which is peculiar because both the old and new lights use LEDs for the turn signal.

That said, I have a 12V source on my harness that's not going anywhere on the new headlight. So I'm far from having this properly hooked up. Anyone with a copy of the pinout for the facelift headlights? That would really put this to bed for me. I can swap wires in the harness but right now I'm really guessing. I don't want to pay for access to the online manual only to discover that the new headlights aren't in there yet.

So if anyone has access to that I would be forever indebted.

In many vehicles turn signals blink fast whenever there is an issue such as a blown light. In this case it could just be due to all the incorrect pins being used.
 
In many vehicles turn signals blink fast whenever there is an issue such as a blown light. In this case it could just be due to all the incorrect pins being used.

Actually it looks like on the non-facelift harness there is a pin for reporting burnt bulbs. I assume I could easily spoof this with a resistor. The new headlight appears to handle all that internally and report through CAN.
 
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No assistance on the pin out, but I'm curious, does the "toy car" on your IC show the headlights on? I have aftermarket LED retrofit lamps installed, to replace original halogens, and the IC shows the lights off all the time. As if they've been burned out. I assume it measures lamp resistance (or something else?), which must be much smaller for the LED.

It does show the lights on. Oddly enough it also shows the turn signal operating.
 
I really thought there would be more interest in retrofitting these than there is but for the two of your apparently interested... ;-)

After more investigation it's looking like it's not easily achievable. The classic light is using voltage to determine whether a light comes on. So when you flip your turn signal on that pin is getting intermittent 12v applied to it each time that light should illuminate. And when you turn on your DRLs that pin gets voltage to denote that the DRLs should be on.

With the new lights that isn't the case (sans turn signals). These appear to just receive power and then there is a signal wire that tells them what should be on and when. Incorporating this into an older car would appear to require a retrofit harness and coding at the very least.

That said, the lights do come on when plugged into the classic car and you could likely make them work as-is. The problem is when the lights have power applied to them the low beams seem to come on by default. And you need 12v power at all times for the turn signal to work. So you can't just cut 12v power when want the headlights to be off because then you'll lose the turn signals. So here was my solution:

Pop the light open and run power directly from the classic harness to each component. So for the DRLs you'd run power from the DRL pin on the harness or the old light controller directly to the DRL board in the new light. Likewise with the turn signals. You'd completely bypass the new controller (which appears to only be providing a ground for this light anyhow). The remainder of the light would effectively be power down until you turn on the headlights at which point you'd provide power to the new light's controller which would turn on it's low beams.

There's a bunch of what-ifs here and you'd almost certainly lose your high beams and wouldn't get the adaptive lighting either though the adaptive lighting is a joke on these lights so you're not missing anything.

Full disclosure: there are people way smarter than me that might look at this, realize the stock harness already has the needed CAN connection and determine that all that's needed is some coding and a few pins moved. That's an unlikely scenario given Tesla probably wouldn't just move pins for no reason at all but it could exist. More likely, if they end up offering a retrofit it will be in the form of a new headlight harness and some coding, similar to the folding mirror, parking sensor and TPMS retrofits.

Cliffs: For anyone wondering if this headlight will just plug into the old car and work, the answer is no.
 
thanks for the write up! I really was hoping for an adaptive headlights retrofit. Its hard to see on dark curvy roads. I almost hit a deer last night going around a corner where the lights didn't shine. Its on of the few things I really miss on my BMWs.
 
thanks for the write up! I really was hoping for an adaptive headlights retrofit. Its hard to see on dark curvy roads. I almost hit a deer last night going around a corner where the lights didn't shine. Its on of the few things I really miss on my BMWs.

I wouldn't bother because I know what you're talking about. Before the S I had a 535d, M5, 535i and a 550i. I love my BMWs. You're expecting the primary beam of light to move as it did on the BMWs. For those not familiar, the BMW projector was able to move left to right in conjunction with the steering wheel. So when you were on a sweeping turn the lights would be pointing around the turn versus straight ahead of you. The LED lights on the Model S are not like this at all.

On the S the adaptive lights are 3 bowls of LEDs in each headlight module that come on with steering wheel position but at best could be considered low speed cornering lights. They do not bend around a curve like the BMWs. Honestly, calling these lights adaptive in the sense that people are accustomed to is a bit disingenuous because anyone coming from a car with true adaptive lights is going to be really disappointed in the Tesla's adaptive LEDs.

So you might be thinking "well hey! At least the LEDs are brighter than the HIDs!". They are a higher color temperature so they appear to be brighter but in practice they are as bad an LED headlight as I've seen. In fact, they're probably the worst. Much like Tesla used a really sub-par HID projector, it appears they mailed it in with the LED lights as well. The beam is very concentrated and full of hot spots. The LED lights in my 535d bathed the road in a white blanket of light. They were amazing. The LED lights on the facelift S have a comically bad beam pattern. A clean cut-off for sure, but below that it's a mess. Fortunately, or unfortunately for Tesla, the HIDs are also terrible so the LEDs do represent a minor upgrade in functionality but the majority of what you're getting is aesthetics. The luminescent DRLs and the overall look of the lights are why you're upgrading.

Disappointing because it appears the X is better in this respect.

Here's what I'd LOVE from a company that can make a car that drives itself. My BMW had LEDs that would split their beam or turn part of it off so that it could be on high beam 70 - 80% of the time. So if I'm on the expressway I have my high beams on and when a car appears in front of me they don't shut off. They simply split. So the left light aims left and the right aims right and they made a tunnel of darkness that would follow the car in front of me. If that car entered a sweeping turn my headlights would move so that tunnel of darkness stayed with it. Once I got close enough to that car where it couldn't make that tunnel any more it would shut off the high beams but keep the right high beam on and pointed up to illuminate road signs. On a two lane highway with approaching traffic it would split the beam around the approaching car until it got close enough that only the left high beam shut off for a brief moment until the car passed and then popped right back on. This feature alone regularly tempts me to look into another 535. You have to have the car coded to do this in the US since DOT hasn't approved it but the tech is on all LED equipped 5 series with the drivers assistance plus package. Here's a video that shows what I'm talking about.

This video does a good job of showing what we should aspire to.

 
If it's controlled through CAN bus, could the last piece of the puzzle be a software setting update? Do you think it may be worthwhile to check with SC just to see if they could do you a favor by checking if there is a software register to be updated?
It's possible, just possible, that you have already got most of the wiring figured out. Really just need to update a register in the software. I did something a while back, to upgrade our Mercedes from Halogen to HID, there was a software setting that I needed to do. Of course, Tesla may be different. Maybe give it a try since you have bought them already?
I have a classic MS, and I am very interested if you can make this retrofit work. The new headlamp is truly cool. =)
 
I suspect the last piece of the puzzle is just coding the car to tell it to interact with the lights differently. I don't see how it would work without at the very least, a new harness from Tesla because the headlight has pins where the old harness doesn't and the old harness has pins where the new headlight doesn't. Not only that but the pin the old harness uses for low beam power is a pin the new headlight is expecting constant 12v power from.

I don't believe there's a CAN connection to the old lights. I can't see what it would be used for since there's a direct wire to address each function.

My SA is awesome but he said that he asked and was told the wiring was proprietary and not yet released. D'oh. He did say that he thought he heard a retrofit was in the works but when he searched for it he came up empty. It seems like a fairly straightforward change if it's just a matter of adding a CAN connection to the harness. A retrofit could tap into the bus and then adapt each stock plug. It's $700ish per light. If they offered this for $2000 as a full kit with install I bet they'd have a line of people throwing money at them. If people are paying $1250 for that new console I can't see them not paying nominally more for these lights.
 
There have been a lot of post's of people complaining about DRL on the faceliftet model. Problems that where solved via FW.
So you pretty much found out youself that a easy retrofit was not possible because the LED light are controlled via CAN bus data.
But thank for trying - somebody has to try it ;-) Hopefull Tesla will offer this upgrade. But historically Tesla has no interest in such "aftermarked" sales - I wounder why ? (I could use a power liftgate on my mid '15 model without premium package)
 
But historically Tesla has no interest in such "aftermarked" sales - I wounder why ? (I could use a power liftgate on my mid '15 model without premium package)
My guess would be three-fold:
1. The cost of engineering a robust upgrade, then training the techs to perform the upgrade and then how to service cars with the upgrade. Lots of cost, possibly no net return on investment.
2. The opportunity cost - those engineers working on #1 could be working on Model 3 or future cars - Tesla doesn't have unlimited engineering resources
3. SC are busy servicing current customers. Adding retrofit customers to the mix would just make queues longer.
 
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