Are you trying to use 4157 NA bulbs in a 4157 "NAK" applacation?

I hate to even start a thread on such a matter but yesterday I had one of my DRL front lights go out. So later in the evening, I stopped into the parts house went ahead, and bought a new 2 pack of Sylvania’s.

So I went ahead and replaced them both as my experience is one usually follows the other pretty quickly.

Well, today I’m driving and I noticed I have the hyper flash this time on both the
L & R. I have a look and both of them are out. I’m suspecting a fuse after 200,000 miles. So I was starting my process of animation testing when Tacoman45 offered this and nailed it.


Not sure if this is going to solve your problem, but make sure you're using the correct 4157 "NAK" bulb for your DRL's. The regular 4157 NA bulbs can't handle the heat/power being dumped into them and they can blow out pretty quickly or even melt at the base. I had the same problem with blown bulbs and it completely disappeared after plugging in the correct bulbs from Toyota.

Apparently, the NAK bulbs use krypton gas inside the bulb to keep the element and bulb housing cooler than the regular 4157 NA bulbs do, in case you were wondering why there's a difference between the two. I believe the regular bulbs use Argon or some other lighter weight noble gas inside the bulb.

This is really useful information and with it, I have already been able to help two other Taco owners. Thanks for chiming in Tacoman45 it is much appreciated.

 

There is no dedicated DRL fuse, the front turn signals are used for DRL and are powered by the TRN-HAZ fuse 15A in the underhood fuse box. They are controlled by the flasher relay on the steering column.

 

Hey thanks for being so quick to answer, though the link you sent opens up actual code and not a PDF etc.

In your experience are we suspecting a fuse as the lights are out? Or should I be prepared to locate the relay or is it a suspect?

I just went through every fuse under the hood if the one behind the battery box is the only one under the hood. Also checked every fuse behind the change tray lower left driver.

There is not a blown fuse in the truck that I can find. That is if reading through them for continuity with a meter is proper.

 

Not sure, it works fine for me on my phone and PC I'll try adding it again.

I've never had to mess with one but I would verify wiring before replacing the relay, you could check the fuse but I would expect the rears not to work either if the fuse was blown.
Do your tail lights work in the front? I would start with checking powers and grounds at the light sockets with a test light before going anywhere else.

 

thanks for The input, but the link you’re sending just opens a never ending list of actual code and not a PDF. It may be my smart phone or something I’ll try on my laptop when I get home.

 

Not sure if this is going to solve your problem, but make sure you're using the correct 4157 "NAK" bulb for your DRL's. The regular 4157 NA bulbs can't handle the heat/power being dumped into them and they can blow out pretty quickly or even melt at the base. I had the same problem with blown bulbs and it completely disappeared after plugging in the correct bulbs from Toyota.

Apparently the NAK bulbs use krypton gas inside the bulb to keep the element and bulb housing cooler than the regular 4157 NA bulbs do, in case you were wondering why there's a difference between the two. I believe the regular bulbs use Argon or some other lighter weight noble gas inside the bulb.

 

You definitely may be onto something here. I actually just did replace both bulbs and the gentleman at O’Reillys told me to use what he handed me and said it would be a brighter bulb.

I kept the old bulb that was still good, and the package the new ones came in.

I will look into that just as soon as I break free. Thanks for caring enough to offer this information.

It never occurred to me that both bulbs may actually be blown out given the fact that they are both Brand New.

 

You nailed it tacoman45!

I guess I would’ve figured it out by the time I pulled the bulbs. But without the information you provided, I would have most likely put exactly the same ones back in their place.

Excellent diagnosis, thank you for taking the time. Thankfully I still had the packaging. This is a very useful bit of information. There’s no telling how many people have gone through this.

I wonder how good-quality LEDs would stand up? Error-free of course. Is there a tried, tested, and proven best choice for this application?

And while we are on the subject. Are these bulbs to be installed in a certain position? While looking closely at the OEM's that came out, I noticed what looks like a small ARROW indicator on one side of each.

I also can't find any sign that there is a problem with them. That is as far as the elements go they look to be intact.

 

No problem. A Toyota tech helped me out so I'm just doing my part here on the forum and sharing the knowledge. Happy to help.

Generally speaking, the overall consensus is that LED's don't play well with the 2nd Gen lighting control system. You'll get hyperflash if you try to use them, and, added to that, most Chinesium LED's will probably cook themselves in a DRL application. My vote is for you to just run the NAK's since they work well and will not melt the harness in the process.

I've never noticed an arrow on my NAK bulbs, so now I'm wondering if I just overlooked it. Considering what I've read on here, I don't think the reflective housing is directional. Maybe post a picture of the bulb?

 

I just noticed that my 2012 AC drl's are different colors; amber (pass) and clear (drivers). Which is factory color? Thanks

 

Quote;

I've never noticed an arrow on my NAK bulbs, so now I'm wondering if I just overlooked it. Considering what I've read on here, I don't think the reflective housing is directional. Maybe post a picture of the bulb?

Reply;

The NAK's I ordered came in and they do not have the arrow I spoke of. If you look into the receptacle the contacts look to be arranged in such a way as to work one way or the other.

And if so wouldn't this put you in the position of being made to choose which element in the bulb is the continuous DRL and which is the blinker? I am being lazy here hopping for the right answer without having to invest the time to study it to find out.

So does anyone know if this is true? If so which element does Toyota intend to be the DRL and which one is the blinker?

 

There are two elements in the bulb. I don't think the circuit cares which element is in series with which circuit which is why you can install them in any orientation. In other words, the truck will just use one of the elements for blinking and the other element for DRL regardless of how you install it.

 

Yeah, I know this is true for sure as I actually tested it, however unintentional. Though I am left to wonder what Toyota had in mind when they designed the circuits. Do both elements have the same output and or appearance no matter if they are in opposite placement?

Was one of the elements designed to be the blinker and the other a DRL? This could be the case either in position or wattage supplied to each individual element? Just going by what I have noticed with Toyota thus far, they don't seem to leave much to chance.

 

Changed mine with Eiko 81136 4157NALL-4157NAK.

As a rule, I always register in a forum of our vehicles or expensive equipment. I have found them a valuable resource when researching mods, repairs, issues and parts.

From this latest issue (daytime running lights) I recommend looking parts up in your service manuals, calling a dealership parts department (don't buy there) or in forums. Don't trust auto parts stores! Also, always install "Long Life" krypton charged bulbs if available. I got my info from Tacoma World.

Photo shows the result of installing the wrong amber bulb. "NA" after # means amber. Passenger side was the factory original 4157NAK. The glass bulb was loose in it's holder. Luckily the socket was still good, slightly browned but not melted.

 

Oh wow - thanks for the info! I just replaced the drl's with regular 4157's & they wouldn't fit. I had to grind off a plastic tit on the bulb base to get them installed. Now I know why they wouldn't fit...

 

No worries, but it was Tacoman45 that saved the day with the right bulb call out. But also, I was under the impression that the 4157NA snap right in. The issue is the fact that the standard NA's heat up and blow out pretty quick, In my case in an hour or so.

I'm not a tech but I respectfully offer that you might do a little research before removing tabs or ears to force-fit any of your Tacos electrical components etc...

It sounds like you are like me and accustomed to the old days of 12V is 12V so no harm done. I am learning daily just how complex our Tacos systems are. Frankly, I feel lucky that I haven't caused any harm myself given my 60's auto mindset. Peace, Love, & Taco's

 

Kudos Tacoman45. Just thought I would add a photo and a couple pennies.

 

Thank you guys for all the good info about the 4157NAK (Krypton) bulbs.
I Changed all the bulbs in both headlight housings today on my 2012 SR5; noticed something interesting I thought I would share.

For the turn signal bulbs that call for 4157 NAK, I found the pictured Sylvania bulbs at Autozone.
The package is labeled 4157 NA, but the bulbs inside have 4157 NAK printed on them (see pic).
So I assume these are Krypton, even though not labeled as such. They seem to be holding up for now, I'll update if they blow in a day or two.

UPDATE: They both blew in about 2 hours. So much for Sylvania. Currently have some OEM bulbs on order from Toyota.
If they don't work I might try the LEDs Mr. Pearson had success with. Thanks for the info!

Also I threw in a pic of the amber marker bulbs on the headlight corners, they are sylvania 2827 amber. The owner's manual doesnt give a number for these.

 

Good contribution, thanks po35042!