whitex
Well-Known Member
- Joined
- Jul 30, 2021
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- WA, USA
- Vehicles
- 2023 Taycan TCT, 2024 Q8 eTron P+
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- #1
One of the few things I knew I wanted to change on my Taycan since I got it was the rear tail lights. I personally very much dislike the dual purpose stop/turn lights. They are ambiguous, i.e. takes more time for someone looking at it to distinguish turn vs. stop signaling, even more time if the view of the rear end is obstructed so you cannot see the entire back of the car. They are also limited in functionality, for example if you turn on your hazard lights, you have now lost most of your stop signaling functionality (your left and right tail lights turn into dedicated turn signals, stop signaling function is gone, leaving only the middle light). If interested, this guy goes into a lot more details:
https://www.youtube.com/watch?v=O1lZ9n2bxWA&ab_channel=TechnologyConnections
For those who don't have a North American Taycan, here is how the standard tail lights work.
So I decided to fix them, to improve the functionality and safety of my vehicle. You’d think it should be easy enough, given Taycans in the rest of the world already have proper tail lights. Unfortunately, since Porsche is not making all their technical information publicly available, it took some reverse engineering, which means time investment. This post is meant to save this time for other trying to do the same (or in some cases, I heard people have hit a dead-end with this, with multiple Porsche dealers stumped by this).
I built myself some extensions for the tail lights with breakout board for easy probing, like this:
and went old school signal probing.
And some lab bench testing:
However, you don’t have to do any of that, as you can benefit from my effort. I am posting below what you need to know if you want to swap your tail lights. I also found out that it’s very possible that the Taycan factory tail lights might already support animation, but posted that speculation, and information for others to follow up I they are interested, in a separate thread.
So what does it take to swap your lights?
WHAT YOU WILL NEED:
RETROFIT STEPS:
Step 1: Recode Rear BCM (a.k.a. BCM2)
I suggest doing this step first to make sure you can in fact recode the BCM2, or else you will be stuck with some really odd functioning tail lights at the end of step 5 if you just swap in the Euro lights – the outside turn signals will light up together with stop lights, stop lights with still serve as turn signals, and the center light bar turn signal will not function at all. There is post here which has a short video showing how this looks. This is what brake lights look like in that case:
It would drive me nuts to drive something like this, hence my suggestion to recode first. However, with all of the above said, technically you can do this any time you want, even at the very end.
To recode the BCM2 you will need access to PIWIS3. You may be able to just pay your dealer to do it. The steps are as follows:
Braking:
Turn signal:
Step 2: Make the connectors fit
The two options here are either swap the 4 connectors on your car’s harness, or just file down the Euro key tabs on the light so that they can fit the North American harness connectors. I went with the latter, filed down the key tabs on the 4 connectors on the 3 light pieces, to allow the US keyed harness to plug into them.
Euro connector on the lights:
N.A. connector on the harness:
After filing it down:
Here is a good comparison using pictures by another member from this post.
Step 3: Remove old lights
I have a Cross Turismo, so I will show the steps required to do it here. For sedan, it is slightly more complicated, but search the internet (or even this forum) and I know there is information on how to do that. For the Cross Turismo:
Side lights are held by one 10mm screw on the inside of the trunk. Just carefully pry off the plastic cover, and the screw is right there.
The center light is held with 5 screws. To get to middle 3 you will have to remove the bottom hatch panel (it is all held on just slips, no screws) and the orange weights (blocking the middle screw access). Picture below shows the location of the 5 screws:
The side screws are hiding under plastic covers, one on each side, which also pries out, but be careful prying, one of the tabs (rear most) is really stubborn an easy to break off (though don’t fret if you do break it, it can be remedied with some Velcro instead, or even nothing, as the other tabs will hold the plastic cover nice and tight anyways).
Once unscrewed, the center light bar just slides out. Make sure you disconnect the connectors on each side before fully removing it.
Step 4: Add missing wires to the harnesses
At this point you need to add 1 wire to each of the center light bar connectors. You need to add PIN5 to both of them (one is a 6 pin connector, one is an 8-pin connector). Here is a picture the right, green connector:
You need to wire the pin 5 into the car. I ran the wire together with the original harness.
Repeat the same with the 8 pin connector on the left (also pin 5 needs to be wired in).
For those interested in the tail light pinouts, here is what I figured out them to be:
As you can see, the side lights are already wired for separate turn signal, only the center lights for some reason were not. You are adding pin 5’s to both center tail light connectors.
Step 5: Install the new lights
At this point you can install the new lights. They will not be 100% working as Euro light yet, but they will mostly work, and the size of the working parts is already larger than a Model Y turn signal for example.
IMPORTANT: at this stage, even though the lights are mostly working, you will be getting errors on the instrument cluster about the missing center tail light turn signals, like this:
The turn signal sound will also be sped up to indicate an error, even if you dismiss the warning on the IC.
Step 6: Wire the newly added harness wires to BCM2
To run the wire to the BCM, you will need to run it along the original wires in the hatch, through the rubber boot that takes you under the roof lining, then to the rear right where the BCM is:
Your end goal is to connect the 2 new wires to the BCM2 connectors shown below:
To run the wire in the hatch, you will have to remove the two remaining panels which are secured by 1 screw each. After unscrewing you can just pry the panels to remove them, run the wire along existing harnesses.
To get to the BCM 2, you will need to:
Then add Pin 7 to the yellow/orange connector and connect it to the right signal wire.
Next, connect the left signal wire to the grey wire which is already connected to pin 2 of the black connector. If pin is missing there, add a pin like to the yellow/orange connector. I’m only saying this because the grey wire doesn’t seem to be wired to anything (disconnecting it will not change any behaviors or throw errors, but I left it connected just in case).
Step 7: Put everything back together in reverse order.
You are done. Your new lights should work like this now.
If you had ran the lights before you’re all done, you might want to also go back to PIWIS and clear all faults from BCM2 (caused by the IC warnings you saw). This is not necessary, but a good cleanup habit after the job is done.
I hope this helps someone. Had I had this information I could have done this swap in a about a day, instead of couple of weeks (on and off, had to put the car back together to use it in between reverse engineering the car for this).
EDIT:
WARNING! If you do this conversion and you are or plan to use the trailer plug on the back of the car, please verify that the trailer lights are still working correctly (I had no bike rack with tail lights or trailer for my Taycan to verify). The 12 pin connector does have separate turn signals, so it will probably be ok, buy you need to verify if planning on using the trailer connector.
https://www.youtube.com/watch?v=O1lZ9n2bxWA&ab_channel=TechnologyConnections
For those who don't have a North American Taycan, here is how the standard tail lights work.
So I decided to fix them, to improve the functionality and safety of my vehicle. You’d think it should be easy enough, given Taycans in the rest of the world already have proper tail lights. Unfortunately, since Porsche is not making all their technical information publicly available, it took some reverse engineering, which means time investment. This post is meant to save this time for other trying to do the same (or in some cases, I heard people have hit a dead-end with this, with multiple Porsche dealers stumped by this).
I built myself some extensions for the tail lights with breakout board for easy probing, like this:
and went old school signal probing.
And some lab bench testing:
However, you don’t have to do any of that, as you can benefit from my effort. I am posting below what you need to know if you want to swap your tail lights. I also found out that it’s very possible that the Taycan factory tail lights might already support animation, but posted that speculation, and information for others to follow up I they are interested, in a separate thread.
So what does it take to swap your lights?
WHAT YOU WILL NEED:
- European tail lights (a set of 3) for your car (sedan or sport turismo). You can get them from Porsche dealers in the US, I got mine online here (you can also get it with blue PORSCHE logo here - as a matter of fact, a whole new set of tail lights costs about the same as the optional blue logo upgrade at order time):
- Access to PIWIS3 to recode your car. Other OBD2 scanners may be able to do it, but you’ll have to figure out yourself the steps. You can probably pay your friendly dealer to do the recoding as well.
- Automotive harness tape – something like this from Amazon.
- Some Torx screw drivers (sorry, don’t remember all, but I think T20,T25 and maybe T30)
- 10mm socket drivers
- M8 star bit (a.k.a. tripe square M8) which looks like this:
- 2 pins you need to add to the 6 and 8 pin connectors for the center lights. You can get then from a similar connector, or a set of spare pins you can buy on Amazon, like this one (I circled the ones which I used from this kit):
Here is what the pin looks like (this is one of the ones I added):
- 2 6m rolls of AWG20 automotive wire like this AWG20 with silicone insulation from Amazon:
- 1 or 2 pins for the VW/SKODA 17 pin connector. You can get one on Amazon for a premium $40 price (which will get you 14 pins like the on you need) here:
Or if you plan ahead you can find them on places like AliExpress way cheaper, like this one for $2.
RETROFIT STEPS:
Step 1: Recode Rear BCM (a.k.a. BCM2)
I suggest doing this step first to make sure you can in fact recode the BCM2, or else you will be stuck with some really odd functioning tail lights at the end of step 5 if you just swap in the Euro lights – the outside turn signals will light up together with stop lights, stop lights with still serve as turn signals, and the center light bar turn signal will not function at all. There is post here which has a short video showing how this looks. This is what brake lights look like in that case:
It would drive me nuts to drive something like this, hence my suggestion to recode first. However, with all of the above said, technically you can do this any time you want, even at the very end.
To recode the BCM2 you will need access to PIWIS3. You may be able to just pay your dealer to do it. The steps are as follows:
- Go to Vehicle Maintenance
- Change the following two values:
- Save the new values
- Go back to ECU list, select BCM2 and Auto Code (not Program) it
- Go back to Vehicle Maintenance and change the values from step to back
- Save the restored values
Braking:
Turn signal:
Step 2: Make the connectors fit
The two options here are either swap the 4 connectors on your car’s harness, or just file down the Euro key tabs on the light so that they can fit the North American harness connectors. I went with the latter, filed down the key tabs on the 4 connectors on the 3 light pieces, to allow the US keyed harness to plug into them.
Euro connector on the lights:
N.A. connector on the harness:
After filing it down:
Here is a good comparison using pictures by another member from this post.
Step 3: Remove old lights
I have a Cross Turismo, so I will show the steps required to do it here. For sedan, it is slightly more complicated, but search the internet (or even this forum) and I know there is information on how to do that. For the Cross Turismo:
Side lights are held by one 10mm screw on the inside of the trunk. Just carefully pry off the plastic cover, and the screw is right there.
The center light is held with 5 screws. To get to middle 3 you will have to remove the bottom hatch panel (it is all held on just slips, no screws) and the orange weights (blocking the middle screw access). Picture below shows the location of the 5 screws:
The side screws are hiding under plastic covers, one on each side, which also pries out, but be careful prying, one of the tabs (rear most) is really stubborn an easy to break off (though don’t fret if you do break it, it can be remedied with some Velcro instead, or even nothing, as the other tabs will hold the plastic cover nice and tight anyways).
Once unscrewed, the center light bar just slides out. Make sure you disconnect the connectors on each side before fully removing it.
Step 4: Add missing wires to the harnesses
At this point you need to add 1 wire to each of the center light bar connectors. You need to add PIN5 to both of them (one is a 6 pin connector, one is an 8-pin connector). Here is a picture the right, green connector:
You need to wire the pin 5 into the car. I ran the wire together with the original harness.
Repeat the same with the 8 pin connector on the left (also pin 5 needs to be wired in).
For those interested in the tail light pinouts, here is what I figured out them to be:
As you can see, the side lights are already wired for separate turn signal, only the center lights for some reason were not. You are adding pin 5’s to both center tail light connectors.
Step 5: Install the new lights
At this point you can install the new lights. They will not be 100% working as Euro light yet, but they will mostly work, and the size of the working parts is already larger than a Model Y turn signal for example.
IMPORTANT: at this stage, even though the lights are mostly working, you will be getting errors on the instrument cluster about the missing center tail light turn signals, like this:
The turn signal sound will also be sped up to indicate an error, even if you dismiss the warning on the IC.
Step 6: Wire the newly added harness wires to BCM2
To run the wire to the BCM, you will need to run it along the original wires in the hatch, through the rubber boot that takes you under the roof lining, then to the rear right where the BCM is:
Your end goal is to connect the 2 new wires to the BCM2 connectors shown below:
To run the wire in the hatch, you will have to remove the two remaining panels which are secured by 1 screw each. After unscrewing you can just pry the panels to remove them, run the wire along existing harnesses.
To get to the BCM 2, you will need to:
- Remove the floor panel which is secured with the two screws holding the luggage clips. Slide it backwards after unscrewing to release the back mounts.
- Remove the rear panel (the one on the very back wall of the car), it's just clipped on
- Remove the speaker grill (pry gently)
- Remove the panel which has the seat belt going through it:
- Unscrew the 3 screws holding the side panel (see previous picture)
- Remove the luggage clip on the back wall holding the side panel
- Gently pry the side panel
- Disconnect the 12V socket and trunk light before removing the side panel
Then add Pin 7 to the yellow/orange connector and connect it to the right signal wire.
Next, connect the left signal wire to the grey wire which is already connected to pin 2 of the black connector. If pin is missing there, add a pin like to the yellow/orange connector. I’m only saying this because the grey wire doesn’t seem to be wired to anything (disconnecting it will not change any behaviors or throw errors, but I left it connected just in case).
Step 7: Put everything back together in reverse order.
You are done. Your new lights should work like this now.
If you had ran the lights before you’re all done, you might want to also go back to PIWIS and clear all faults from BCM2 (caused by the IC warnings you saw). This is not necessary, but a good cleanup habit after the job is done.
I hope this helps someone. Had I had this information I could have done this swap in a about a day, instead of couple of weeks (on and off, had to put the car back together to use it in between reverse engineering the car for this).
EDIT:
WARNING! If you do this conversion and you are or plan to use the trailer plug on the back of the car, please verify that the trailer lights are still working correctly (I had no bike rack with tail lights or trailer for my Taycan to verify). The 12 pin connector does have separate turn signals, so it will probably be ok, buy you need to verify if planning on using the trailer connector.
Last edited:
? How often do you see the taillights of your car
