Anyone thinking about converting halogen to LED should read this from Daniel Stern Lighting: Daniel Stern Lighting Consultancy and Supply

Given all the LED junk that is coming from China, even if you get them to play nicely with the systems in the vehicle, they are not the upgrade everyone thinks they are. The article mentioned does a good job of explaining why. Some of the better quality companies are working on a true conversion bulb for halogen but they won't be the $29.95 a pair from China ones. Properly designed, built with quality solid state components and then cycle tested, they will probably be $200-$300 a pair but actually be an improvement with proven longevity. In the meantime, stick with stock no matter the year of your 4R.

A good rule to follow almost always when troubleshooting electrical weirdness is to suspect and check aftermarket parts that have been installed. By a large margin, electrical problems I read about on here occur on modified vehicles. I think remote starts and aftermarket lights are the most common. In my case, an aftermarket remote start took a battery, starter, and alternator with it when it failed. So if you can, electrically remove non-stock items first when troubleshooting.

Great information. I’ve had LED headlights for years, first Auxbeam high/low beams and have since switched to Boslla B4 Bullets in the lows. LED fogs too. So far, all has been good but I am very happy that this will be in my knowledge base should codes start showing.

Thanks for that refresher. If anyone wants LED headlights they should do it properly: install Toyota OEMs. There are several threads here discussing how to make this conversation.

Still working fine. No heat issues with the Beamtech led bulbs without a fan.

Same here. Closing in on a year with Beamtech fan-less bulbs and no issues at all. Thought for sure that an Arizona summer might push them to the limit, but still good.

Another vote for beamtech, I've been running the low beams for almost exactly two years now with no problems

I had actually forgotten this thread when I was on vacation a couple of weeks ago 1200 miles from home. My wife was driving and suddenly said, "Why's this red 'BRAKE' light on?" The usual orange stack on the right was lit up too. I told her, "I remember reading something about this and it's not a big deal." Read the codes, found this thread, took out my Boslla LEDs in favor of some halogen bulbs, and no more issues. A shame b/c I loved the Bosllas and they had caused no previous trouble from when I got them in 2021.

Well, I am REALLY hoping the expensive Morimoto 2Stroke bulbs are worth their price...I'm shifting from HID to LED and I hope to NOT have these issues...but if I do, it's nice knowing what the reason is for! I'll report back after I get them installed and driven with for a while.