Tail Light Retrofit- AMBER turn signal

One thing I've always hated about my 3 was how they use the Brake light as the turn signal. I'm a big believer in a dedicated color(amber) for turn signal. Unfortunately a lot of manufactures are going away from that in favor for the brake/turn combo. Maybe it's cost savings.IDK, but I am out to change that.

I started looking into just purchasing the European model 3 Tail lights which have an amber turn signal factory(its required by law over seas to have a orange signal). The problem I ran into was the US spec cars are programmed to use the brake AS the turn signal. Which means than even if I got a European lamp, i would still need to find a way to change the computer system to flash a dedicated output for the turn signal.

So I purchased a set of stock tail lights and cut them apart. While inside I painted the chrome black which gave i a much cleaner look. Then I retrofitted a 3" Diode dynamics HD amber LED strip where the OEM reverse was. For the reverse, I retrofitted a 3" white LED strip right next to it(inner). The wiring was a bit tricky as I had to tap off the 3rd brake light for dedicated "BRAKE" then the front camera side markers for a dedicated "TURN" signal. Overall worked pretty well!

In the trunk, pass side there's a harness. Blue wire is 3rd brake light which is where I tapped off.

Running the turn wires through the trunk boot. fun stuff

here's a video showing the functions. They might look dim, but its out in direct sunlight. I assure you they are bright
Also you may notice they are hyperflashing because the car isn't seeing any load(i disconnected the stock brake/turn wire) I left them as is, but if it get annoying I will throw a resistor in there.

Also Decided to do blackout headlight, and AMBER DRL mod

 

[MambaKhanMD]

It won't work on any inner taillight that isn't global. Those are 4 pin inners and will require a new trunk harness as well. If your car came with global outer and inner taillights (2023+), you can activate rear fog via gateway config or S3XY buttons and they will work.

Aftermarket tails have red fog built in, with 4 pin harness. Figuring out a non-gateway config solution this weekend for rear fog and fixing amber and brake turning on same time for older cars.

People exploiting 300$+ for this is insane.

 

[E90alex]

Aftermarket tails have red fog built in, with 4 pin harness. Figuring out a non-gateway config solution this weekend for rear fog and fixing amber and brake turning on same time for older cars.

People exploiting 300$+ for this is insane.

People have done it in the past with custom wiring if you don’t mind splicing wires and pulling interior panels. For rear fogs you would need to wire a physical switch. No way to get the button to show up in software without coding.

 

[Durzel]

OK so I bought a couple of these cables from EVOffer to try and retrofit twin reverse and fog lights to my car.

I bought a couple of “global” 4 pin inner taillights for this purpose, and my car has always had the rear tail lights coded to “Global”.

The first surprise I had was that I thought I needed to buy two cables, but in actual fact one cable has two of each 3 pin female and 4 pin male connector, with enough slack to go across the trunk lid. In other words, one cable converts both lights.

Unfortunately, the reversing and foglights appear to be reversed when installed. Putting the car in reverse illuminates the rear foglights (both sides) and putting the rear foglights on turns on both white reversing lights.

Any thoughts on how I can diagnose where the problem is? Tail lights? (a pattern part, not OEM), the converters, or the coding?

 

[kodenco]

OK so I bought a couple of these cables from EVOffer to try and retrofit twin reverse and fog lights to my car.

I bought a couple of “global” 4 pin inner taillights for this purpose, and my car has always had the rear tail lights coded to “Global”.

The first surprise I had was that I thought I needed to buy two cables, but in actual fact one cable has two of each 3 pin female and 4 pin male connector, with enough slack to go across the trunk lid. In other words, one cable converts both lights.

Unfortunately, the reversing and foglights appear to be reversed when installed. Putting the car in reverse illuminates the rear foglights (both sides) and putting the rear foglights on turns on both white reversing lights.

Any thoughts on how I can diagnose where the problem is? Tail lights? (a pattern part, not OEM), the converters, or the coding?

Since you're already solving this using a converter, I would just pin out with a multimeter what pin does what on the converting harness, and depin/repin them so the correct lights illuminate. You probably just have to swap 2 pins on whichever side harness plugs into the vehicle side harness.

 

[Durzel]

Since you're already solving this using a converter, I would just pin out with a multimeter what pin does what on the converting harness, and depin/repin them so the correct lights illuminate. You probably just have to swap 2 pins on whichever side harness plugs into the vehicle side harness.

Dumb question but how do I actually do this with a multimeter?

Is it not peculiar that it is wrong on both sides, it would mean the connector is wrong on both ends? What I mean is rather than the cable being a simple short 3-pin to 4-pin adapter - it goes between both tail lights, and plugs into both vehicle 3-pin connectors, if that makes sense.

 

[terranx]

Dumb question but how do I actually do this with a multimeter?

Is it not peculiar that it is wrong on both sides, it would mean the connector is wrong on both ends? What I mean is rather than the cable being a simple short 3-pin to 4-pin adapter - it goes between both tail lights, and plugs into both vehicle 3-pin connectors, if that makes sense.

Flip the 3 pin connectors around

 

[kodenco]

Flip the 3 pin connectors around

lol, this might actually work. @Durzel try this first.

 

[Durzel]

As in swap the left and right sides?

The 3 pin connector is keyed (as is the 4 pin one)

I’m wondering whether coding my rear lights to “global” is messing it up. Do US owners have to do this when they fit the global/Euro rear inners?

 

[terranx]

As in swap the left and right sides?

The 3 pin connector is keyed (as is the 4 pin one)

I’m wondering whether coding my rear lights to “global” is messing it up. Do US owners have to do this when they fit the global/Euro rear inners?

Left and right yes. I suspect your harness is meant for LHD vehicles which have the rear fog and reverse lamp sides reversed.

US cars don't have rear fogs from the factory. If enabled and coded to global (at least 2021+ models), the rear fogs are on separate pins altogether.

 

[Durzel]

Left and right yes. I suspect your harness is meant for LHD vehicles which have the rear fog and reverse lamp sides reversed.

US cars don't have rear fogs from the factory. If enabled and coded to global (at least 2021+ models), the rear fogs are on separate pins altogether.

Will give that a try.

I had my rear lights coding changed to “global” recently, when I had my matrix lights fitted. I’m wondering now whether that was a mistake, as my car doesn’t natively have a 4 pin connector on the harness which cars with the global lights from the factory must have. My car was originally on “EU_CN”.

{
"accessId": 67,
"codeKey": "rearLightType",
"content": {
"enums": [
{
"codeKey": "NA",
"description": "Tail light and one light for brake and turn signals",
"products": [
"Lychee",
"Model3",
"ModelY",
"Tamarind"
],
"value": 0
},
{
"codeKey": "EU_CN",
"description": "Tail light, brake light, and turn signal light",
"products": [
"Model3",
"ModelY"
],
"value": 1
},
{
"codeKey": "GLOBAL",
"description": "Rear Global Lamp",
"products": [
"Model3",
"ModelY"
],
"value": 2
}
]
},
"description": "Rear light fixture type",
"products": [
"Lychee",
"Model3",
"ModelY",
"Tamarind"
]
},

Unfortunately switching the coding back is easier said than done as it cost me a few hundred dollars to get it all done in the first place.

Will give the left and right switch a try. I also have a second cable from EVOffer I can try too.

 

[terranx]

My car was originally on “EU_CN”.

From what others have told me, the setting doesn't actually seem to do anything on pre 2021 refresh cars.

 

[Durzel]

From what others have told me, the setting doesn't actually seem to do anything on pre 2021 refresh cars.

Hope so.

Looking at the adapter cable from EVOffer, it doesn’t look particularly easy to depin. On the connector that attaches to the car I can’t see any way of removing the pins at all.

I’ll try and get some photos tomorrow, it’s late here UK time.

Thanks a lot for all your (and others) help.

 

[terranx]

On the connector that attaches to the car I can’t see any way of removing the pins at all.

Can you post a picture? At least on the native connector I don't remember it being too difficult.

Worst case you can cut the wires in the middle and make the splices to the opposite one.

 

[Durzel]

Can you post a picture? At least on the native connector I don't remember it being too difficult.

Worst case you can cut the wires in the middle and make the splices to the opposite one.

Ok grabbed some photos. Hope they help with diagnosis.

Only obvious thing I can see is that on the 3-pin connector end the wire configuration is different on each end, black/red/orange and black/red/purple. Don’t know if this is significant?

 

[E90alex]

Can you not just swap the left and right sides?

 

[Durzel]

Can you not just swap the left and right sides?

That’s what I’m going to try next. It is midnight here so not able to do it now. There was no indication on the cable that it might be specific to each side, and no instructions were given.

 

[terranx]

You should be able to swap sides. But if you can’t the pins on the 4 pin end are easy to remove. Slide open the purple cover and the pins should be possible to pull out.

 

[Durzel]

Thanks. Can definitely swap sides, as the connectors are identical. Will try and do this today (Tuesday) and report back. Thanks again for the help.

 

[terranx]

Ok grabbed some photos. Hope they help with diagnosis.

Only obvious thing I can see is that on the 3-pin connector end the wire configuration is different on each end, black/red/orange and black/red/purple. Don’t know if this is significant?

By that scheme it appears orange is reverse and purple is rear fog.

 

[Durzel]

Haven’t switched it over yet but EVOffer have confirmed on Telegram that the cable IS directional, so to speak.

Thanks again to everyone who helped. I should’ve really tested all the functions before finishing but was on my own and it’s not easy to test foglights and reverse (as you have to be sitting in the car)