Think I found the solution to the dim front turn signals on 18+

So I recently got back into a 2020 Tundra. While trying to make my previous set of VLED Triton 3’s work on the this new truck I ran into some issues. I decided to try moving the wire positions in the 3 pin plug and while it didn’t solve the VLED issue, I did notice that Toyota has (at least on my truck) the wiring on the factory plug wrong. From the factory the directionals are only illuminating the 8w portion of the bulb, when you move the pin to the correct spot the bulb is now putting out the correct 28w. I know many have upgraded to LED’s to get brighter signals, but with the wiring incorrect you’re still only activating the dim setting of the bulb.

 

That is a really Big statement to make. It needs some backing up.

How about you tell us more details, like what wire is in the wrong place and what was changed, perhaps some pics would be in order too.

Thanks this would help us understand better what might be very helpful.

 

https://youtu.be/B5H7OZvDTQE

 

https://youtu.be/sls4UyrdwUg

 

the wiring is setup to use the brighter filament of a dual filament bulb. what you did was change what filament is lit. The issue with LEDS in toyota sockets like this is that the Bulb base from toyota is wired CK style. The quick fix is actually turn signal sockets from a 1st gen scion XB that converts it to 1157 bulb (at least this is what ive done on my avalon and my tundra) No funky wiring of the Ground like the CK style bulb, assuming the base is still the same one on the new trucks like its been on toyotas since the early 2000s


(edit im dumb and saw what you did. ignore me. but the XB socket will fix funky led operation)

 

That’s just it, mine came from the factory wired up to only light the dim filament on turn signals.

 

yea i re-read it and felt dumb. lol! i have to pay attention to the ones that come in now.. thats weird.

 

Interesting will have to look into this, maybe this weekend.

 

Shouldn't there be 3 wires?
2 filaments and ground?

I don't have any issues but some have complained that turn signal is not bright enough.

 

toyota does this on some cars.. if you really wanted you can add a thrid wire to your parking lights and have them on when the park lights are on...

 

My '16 turn signal bulb has 2 filaments and one filament is for turn signal and Daytime Running Light (when turn signal is off) and the other (8W?) Is for Parking light. I haven't looked but there better be 3 wires. lol

But I see what you mean. I think I saw in one of my old cars that had a double filament socket but only one was being used. I assumed since op had a 2020 it was like my '16.

 

So the brown part at the end of the white wire is a plug and you move it from center to outside position?

 

maybe its some option.. i honestly am not sure.

 

I can see in op videos that 2020 has a separate LED DRL. That's why the other filament in the turn signal assembly is not used.

Curious where the parking lights are in 2020? Same as turn signal light I assume unless there is a separate light for that.

 

I just noticed that the passenger side DRL (op video 1) is off while the turn signal is on. This design is consistent with older models (my '16) meaning that the turn signal has priority over drl.
However, the driver side DRL is on when the turn signal (low power) is on!
Something doesn't make sense as far as passenger and driver side DRLs unless op did some other wiring mods.
but at least op rewiring results in a brighter turn signal.

where are the parking lights in 2020? That may help the mystery.

 

I wasn’t completely finished buttoning up the passenger side when I took the vid, the side marker and headlight harnesses were unplugged at the time

 

I need to try that. It seems lot brighter.

 

So, a few points worth mentioning,

the 2018+ OEM LED headlights use a 7444NA signal bulb

the 2018+ with Halogen headlights and LED DRL strip at bottom use a 3157CK signal bulb

The dim portion of the LED DRL acts as the parking light on these models like they have in the past on the 14-17 Platinum and 1794 models that came with the lower DRL strips

Toyota uses the same 3 pin plug on both models (and on my 20 the signal and ground wires were in the same positions as they were on my 16)

When we created the PNP harness to retrofit these LED headlights onto the 14-17’s we noticed that the ground wire needed to be moved from the middle to the outside when using the new style bulb and socket. This change can be seen on any conversion harness that included turn signal adapters, so this issue would only be noticed on trucks with the LED headlights from the factory and not on units that were retrofit using either turn signal adapters or re-pinned using the directions in the 2018+ headlight harness thread in the lighting section


Pic borrowed from iHacker's harness thread

 

I'd be interested to see if this has any long term effects on the life of the signal light bulb or anything like that. I can't think of any reason why switching it should be a problem but who knows why Toyota chose to do it that way?

 

You can check on the wiring without removing the headlamps, just peek down in by the washer fluid res, you'll see the gray plug with two wires. I'm curious how other 18+ are wired.

I have extra parts kicking around, I'm going to make a mock up wire harness and a vid later for the non believers. I'm thinking that the way mine was wired would be perfectly fine if it were plugged into the older 3157CK bulb and socket and not the newer 7444 socket on the truck

 

If it doesn't rain, I'll try to take a peek today.

 

I simply replaced the turn signal with an led bulb from vleds. Problem solved.

 

That solves the brightness problem slightly , but if yours is wired like mine you’re still only utilizing the dim/parking light setting on the bulb. It would be even brighter if the wires were swapped

 

VLED is an effective way to solve the issue, however it is one of the most expensive options.
The OP is indicating that there is a modification to boost brightness that does not cost anything and can utilize current hardware.

 

So after playing around a bit, I noticed that swapping around the wiring made little difference when using VLEDS but that maybe due to the base adapters I’m using. For someone staying stock with the factory bulbs the difference is obvious.

 

https://youtu.be/5ncI6iLY69s
https://youtu.be/itQmHsfFJ8c

 

just did this mod on my 2018 SR5 TRD, LED headlights. Thanks for the write-up, boy does this make a difference in brightness.

 

I just checked mine. The left one (driver's side) has a black wire to the left plug and white wire to the centre plug. The right one has a pink wire to the left plug and white wire to the centre plug. However, they both look plenty bright to me so I don't think I'll do anything with them.

I just realised that I didn't check what my parking lights look like.

 

as far as I know there is no "dim/parking" setting. That is only dictated by which filament you are applying the voltage to. In older models both filaments get the same 12V but it's the light bulb filament (8W in this case) that limits the current and the power & brightness.
Therefore switching the bulb with a LED would also work. You are basically replacing the 8W bulb with LED but still getting the same 12V power. In this case swapping the wires will not provide additional brightness! It may even not work assuming that the LED is a single "filament" light. If the LED is dual LED like old models and one led is brighter than the other (parking vs. turn signal) and it's being used in model cars like yours then swapping wires would make it brighter ... But it seems like there are too many different configurations to consider.

Your method works perfectly if you don't want to switch the bulb. In your case you are switching the wire which is switching the filament from 8W to 28W. Again same voltage to both filaments. You found a nice way to get more light with stock.