UK Tailgate Light 3pin to 4pin Adaptor

[Lardyboy]

Hi All, I have a 2022 M3LR and have managed to get my hands on the tail gate lights with a fog & reverse light on both sides, however these are 4pin and my cars existing harness is 3pin, does anyone know where I can get an adaptor from?

 

[SteelClouds]

This might be an older post but without any response, I'll add mine. I have not seen any adapter for sale. There are few options.. build your own as the connectors are readily available from parts houses like DigiKey and Mouser. Or what I am going to try in a few hours when I have daylight, try to push out the existing pins on the 3 pin connector and move them to a four pin connector. I looked up the data sheet on the pin and I see where the latch needs to be pushed down to remove it. The trick is finding something thin and stiff enough. I dont want to ruin the connector or cut the wires.

Pin details - https://www.mouser.com/ProductDetail/TE-Connectivity/1718760-1?qs=%2BJ%2BJwDEtia0a1oW6Or6DYQ==
pin datsheet with mechanical details = https://www.mouser.com/datasheet/2/418/8/ENG_CD_1418754_D-2006094.pdf
pin sealing boot - https://www.mouser.com/ProductDetail/TE-Connectivity/967056-1?qs=0/gE9CgFqPz6uB5nwJRlHA==
4 pin connector = https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/1-1456426-1/5437232

3 pin connector.. I think - https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/1-1670917-1/10478251

 

[sjkjs]

This might be an older post but without any response, I'll add mine.

I will too, over a year later.

I've successfully done this conversion, Europe (/Australia) 3 pin inner taillight to 4 pin. I removed the pins from the old 3 pin connector and inserted them into the new 4 pin plug. I then spliced into the reverse and rear fog light wires to add the extra wire for the opposite side.

The whole process was quite simple and straight forward. You don't need any special tools to depin the connector. I just used a jeweller's flathead screwdriver. I didn't take any photos and it's a bit hard to describe, but there's a thin plastic strip which holds the pins in place. You lever this piece sideways, and once it's unclipped, it slides the rest of the way out. The pins can then be pulled straight out of the connector with no force required. Once the new pins are installed, the plastic strip slides back in and locks it all together.

 

[pnwadventures]

I will too, over a year later.

I've successfully done this conversion, Europe (/Australia) 3 pin inner taillight to 4 pin. I removed the pins from the old 3 pin connector and inserted them into the new 4 pin plug. I then spliced into the reverse and rear fog light wires to add the extra wire for the opposite side.

The whole process was quite simple and straight forward. You don't need any special tools to depin the connector. I just used a jeweller's flathead screwdriver. I didn't take any photos and it's a bit hard to describe, but there's a thin plastic strip which holds the pins in place. You lever this piece sideways, and once it's unclipped, it slides the rest of the way out. The pins can then be pulled straight out of the connector with no force required. Once the new pins are installed, the plastic strip slides back in and locks it all together.

Were you able to get rear fog lights working then? If so, I’m really interested in following your footsteps. Can you share more details on the splicing you did, where you got the replacement lights(?), how they operate, and any pictures?

 

[sjkjs]

Were you able to get rear fog lights working then?

Yes, but the car originally already had one rear fog light. All I did was add the second one on the other side.

I got the lights off a crashed car from a wrecker. The outer taillights (with the brake and indicator) are a direct plug in with no modifications needed.

The inner lights have 3 pin plugs on the early Model 3s. 1 pin is ground, 1 pin is 12v for the taillight, 1 pin is 12v for the rear fog OR the reverse light. That third pin does the rear fog on the driver's side and the reverse light on the passenger side.

The new inner lights are 4 pin - ground, 12v taillight, 12v rear fog, 12v reverse. I just tapped into the existing rear fog and reversing wires in the harness and added additional wires. So the one wire coming from the harness is doing the lights on both sides instead of just on one side. Ideally you should use something like wire taps but I couldn't find the right size locally and didn't want to wait for delivery so I cut and soldered the wires.

 

[pnwadventures]

Yes, but the car originally already had one rear fog light. All I did was add the second one on the other side.

I got the lights off a crashed car from a wrecker. The outer taillights (with the brake and indicator) are a direct plug in with no modifications needed.

The inner lights have 3 pin plugs on the early Model 3s. 1 pin is ground, 1 pin is 12v for the taillight, 1 pin is 12v for the rear fog OR the reverse light. That third pin does the rear fog on the driver's side and the reverse light on the passenger side.

The new inner lights are 4 pin - ground, 12v taillight, 12v rear fog, 12v reverse. I just tapped into the existing rear fog and reversing wires in the harness and added additional wires. So the one wire coming from the harness is doing the lights on both sides instead of just on one side. Ideally you should use something like wire taps but I couldn't find the right size locally and didn't want to wait for delivery so I cut and soldered the wires.

This is great, thank you. I'll do a little more digging on this as well, but I have a North America 2019 Model 3 - I'm not yet sure what wiring the car has, but I'd like to be able to have two rear fog lights (and of course not screw up the reverse lights). Also, the rear fog lights should only illuminate when the front fog lights are illuminated (I assume that is the behavior for markets that have a single rear fog light).

 

[sjkjs]

Also, the rear fog lights should only illuminate when the front fog lights are illuminated (I assume that is the behavior for markets that have a single rear fog light).

I don't know anything about how the US cars are wired, but I can tell you that on European/Australian cars the front and rear fog lights are controlled separately. There are two independent buttons in the lighting controls on the screen.

 

[pnwadventures]

I don't know anything about how the US cars are wired, but I can tell you that on European/Australian cars the front and rear fog lights are controlled separately. There are two independent buttons in the lighting controls on the screen.

Ahhh. That is the ideal behavior, and matches the behavior of my prior car (North America Audi A4).

As my NA Tesla does not have any rear fog control in the UI, I wonder if this is gated by an unfixable code/region setting, or if it's as simple as detecting the presence of the circuit/bulb (i.e. doing the mod will suddenly result in the feature popping up in the UI). I'll have to investigate some more.