LED mod for 12-Pin turn signal flasher relay w/DRL

[utmba95]

I have not seen any instructions for modifying this relay to use LED bulbs. I ONLY CHANGED OUT THE FRONT TURN SIGNALS TO LEDS, so these instructions may not work if you want to run rear LED bulbs too. I changed mine because the DRLs run so hot they burn up the bulb connector and bulb. I bought cheap bulbs from e-bay and had to file down the base so the width would fit.

12 Pin turn signal flasher relay with DRL (toyota P/N 81980-35020 Denso P/N 066500-5570)

It worked on my 2003 and 2004 4Runners.

Here are the steps:
1. Remove relay (instructions)

2. Remove relay cover

3. Desolder R4 (200 ohm resistor marked 201. 201 = 20 followed by 1 zero) You can alternately heat the sides of the resistor with a soldering iron until it comes off.

4. Replace R4 with approximately 1.8K resistor. I used 1.82K. Ideally you have a size 2010 (5mmx2.5mm) resistor like the original, but I used a 1206 since it was all I had. I had to bridge the solder across gaps to make it fit. I determined this value by soldering on a 10K potentiometer and turning it both directions with the turn signal on. One direction the signal will fast blink, the other direction it will go crazy and then stop blinking. Measure the resistance at both extremes and then take the average for the new value. Note that you have to unplug the relay to measure the resistance as the resistor has voltage on it even when ignition is off, and this messes up the resistance measurement. I didn't measure the voltage to calculate the power, but 1/16th Watt is more than enough for 1.8K.

5. solder a new resistor for R4 (1.82K may work for you)

Here's my debugging in case anybody else wants to improve upon it.

There are probably 3 ways to hack this relay module for LEDs.
1. Change shunt. My guess is you could just exchange the 19milliOhm resistor with one twice as large if you run incandescents in the back. I didn't have such a resistor and didn't want to try to make one. You need the voltage drop to equal 75mV for the amount of current in one front and one back light. If you change the shunt, you also need to consider if it can dissipate all the power if somebody puts in incandescent bulbs.
Measurements courtesy of VE7OSR
2. Change R4 which sets the current sense level. This is what I did. However, I suspect this may not work for LEDs in front and back as the voltage drop across the stock shunt would be almost immeasurable. You could change R4 as well as the shunt to fine tune.
3. Possibly lift pin 1 of IC1 and fine tune a voltage about 75mV less than pin 2 to simulate the proper voltage drop across the shunt. I did not try this, and it would prevent detection of a failed bulb.
I deduced what I could of IC1 - Denso SE336
1 = Right indicator out
2 = VCC (12V)
3 = Left indicator out
4 = Right indicator in
5 = Left indicator in
6 = current sense level adjust (via resistor to ground) Originally 200 ohm
7 = no connect (9V when ignition on)
8 = Hazard indicator in
9 = ? (5V when ignition on)
10 = current sense (measures voltage drop from VCC across shunt)
The "indicator in" signals connect to the turn signal switch and hazard switch. They are pulled up to 12V when off and pulled down through resistors to 3.5V when on.

 

[raptorRunner01]

Has anyone else run this fix for hyper flashing leds? I've got a 2003 SR5 with factory DRLs and the associated 12-pin relay. Already tried resistors before the individual bulbs (only 2 up front) and that didn't work. Can't replace the 12-pin with the tried and true EP35 so I'm out of ideas. Is this solution still the best fix?

OP - any updates as to how this has worked for you or suggestions on how to do it? Thanks!

 

[Mikep.]

I was there when I did my facelift, I switched all the front indicator bulbs to led. I did a lot of digging, but found close to nothing on the matter. I was originally going to solder in a pot, but had trouble finding one within the range that I needed. I do not remember what forum it was, not this one, I stumbled upon a thread where someone filed down the factory bar resistor. This is what I did, I actually used a bench grinder (VERY carefully of course). It has been working flawlessly ever since. It works completely as it should, if I unplug a bulb front or rear, it will hyperflash, so I will know if a bulb goes out. I ended up grinding about half off the factory bar, which is not the conventional style resistor, basically just a metal bar. I have an 03 limited with factory DRL's. I tapped both the upper and lower turn signals on the same circuit, the DRL's have been disabled for a long time before I did this. Rear bulbs are stockers still.

 

[utmba95]

The mod worked well, but unfortunately the cheap Chinese LED bulbs I bought off of ebay didn't. They aren't designed to handle the heat of running continuously, and I melted 4 of them in two different styles. Both had a diode in series with the LEDs that overheated and melted the base.

Rather than sink more time and money, I went back to incandescent.

 

[raptorRunner01]

I was there when I did my facelift, I switched all the front indicator bulbs to led. I did a lot of digging, but found close to nothing on the matter. I was originally going to solder in a pot, but had trouble finding one within the range that I needed. I do not remember what forum it was, not this one, I stumbled upon a thread where someone filed down the factory bar resistor. This is what I did, I actually used a bench grinder (VERY carefully of course). It has been working flawlessly ever since. It works completely as it should, if I unplug a bulb front or rear, it will hyperflash, so I will know if a bulb goes out. I ended up grinding about half off the factory bar, which is not the conventional style resistor, basically just a metal bar. I have an 03 limited with factory DRL's. I tapped both the upper and lower turn signals on the same circuit, the DRL's have been disabled for a long time before I did this. Rear bulbs are stockers still.

Ha! I think I found that exact same post you're talking about. I was wondering how well that mod worked. Makes me nervous since it's such a permanent mod but I guess if it ever fails, you could just always buy a new relay at the stealership and be back to normal. Question though - why did you have to disable the DRL's for this to work? Also, what do you mean by tapping the upper and lower turn signals on the circuit? I thought we only had the lower turn signals in the bumper as active? Thanks!

 

[Mikep.]

I had the same reservations about modifying the stock piece, but if you go slow and are careful you will be fine.
I did not need to disable the drls for this to work. I disabled them when I first got the car, I just thought it was worth mentioning considering it is related to the parking lights.
Correct, ours from the factory only have turn signals in the bumper, but when I did the facelift (06+ headlights), I wanted the turn signals in the new headlights to function with the stock ones in the bumper so I linked them together.
Hope this helps.

 

[Krayziekid]

I had the same reservations about modifying the stock piece, but if you go slow and are careful you will be fine.
I did not need to disable the drls for this to work. I disabled them when I first got the car, I just thought it was worth mentioning considering it is related to the parking lights.
Correct, ours from the factory only have turn signals in the bumper, but when I did the facelift (06+ headlights), I wanted the turn signals in the new headlights to function with the stock ones in the bumper so I linked them together.
Hope this helps.

Quick question, cause I am about to do the 06 headlight facelift. Do you have any pics of the install, or your current wiring?

So did you simply splice into the power and ground coming up from the bumper and put an amber bulb into the turn signal socket up top in the new 06 lights? Do those top bulbs also function as DRLs?

And finally, do you know if it is possible to get a second DRL 12 pin relay thing? I want to try grinding it down or sanding it down somehow, but I am not too keen on doing it on my stock one. I'd much rather have a backup I can play with and swap out if it works. Sorry for all the questions.

 

[Mikep.]

Quick question, cause I am about to do the 06 headlight facelift. Do you have any pics of the install, or your current wiring?

So did you simply splice into the power and ground coming up from the bumper and put an amber bulb into the turn signal socket up top in the new 06 lights? Do those top bulbs also function as DRLs?

And finally, do you know if it is possible to get a second DRL 12 pin relay thing? I want to try grinding it down or sanding it down somehow, but I am not too keen on doing it on my stock one. I'd much rather have a backup I can play with and swap out if it works. Sorry for all the questions.

I do not have any pictures of the wiring or the install, just the finished product. Very basic install though. I picked up the bulb sockets for the new turn signals in the headlights and tapped them into the factory ones in the bumper. My DRLs are disabled, the top bulbs function exactly as my lower ones do.
You can get a second flasher either from the dealer or salvage yard. A dremel with a sanding drum would probably be the tool of choice for this. Just take it slow and file it down a little at a time and you will be fine.

 

[Krayziekid]

I do not have any pictures of the wiring or the install, just the finished product. Very basic install though. I picked up the bulb sockets for the new turn signals in the headlights and tapped them into the factory ones in the bumper. My DRLs are disabled, the top bulbs function exactly as my lower ones do.
You can get a second flasher either from the dealer or salvage yard. A dremel with a sanding drum would probably be the tool of choice for this. Just take it slow and file it down a little at a time and you will be fine.

Ok thanks. Are they disabled on purpose? Or is that because of the new wiring? I'm trying to decide if upper and lower DRLs/turn signals are too much lol.

 

[Mikep.]

Yes, they are disabled on purpose. I personally do not like the look of DRLs at all. Was one of the very first things I did to the car.

 

[cmpt1]

I deduced what I could of IC1 - Denso SE336
1 = Right indicator out
2 = VCC (12V)
3 = Left indicator out
4 = Right indicator in
5 = Left indicator in
6 = current sense level adjust (via resistor to ground) Originally 200 ohm
7 = no connect (9V when ignition on)
8 = Hazard indicator in
9 = ? (5V when ignition on)
10 = current sense (measures voltage drop from VCC across shunt)
The "indicator in" signals connect to the turn signal switch and hazard switch. They are pulled up to 12V when off and pulled down through resistors to 3.5V when on.

In addition sample SE336 circuit

 

[merlinrunner]

Has anyone got a wiring diagram showing which wires to splice into a load resistor for rear LED turn signal mods? Specifically for a '06 TFR. Been searching the posts but don't see anyone doing the resistor mod for rear turn signals. Maybe its in the "To hard to do category"? I can't use a 8 pin flasher...DRLs.

 

[thomaspuzio]

Why isn't there a 12-pin LED flasher relay that we can just plug and play like all the other flasher relays out there? I can't believe to fix this we have to crack open the stock relay and break out the soldering iron. You're telling me NO ONE has made a part I cant just plug in??

 

[bearisasquare]

Why isn't there a 12-pin LED flasher relay that we can just plug and play like all the other flasher relays out there? I can't believe to fix this we have to crack open the stock relay and break out the soldering iron. You're telling me NO ONE has made a part I cant just plug in??

That is correct. I did this to my 2009 and now have LED's everywhere. This is the best and easiest solution i found

https://www.tacomaworld.com/threads/12-pin-dtrl-led-flasher-modification-2012-tacoma.244028/page-4

 

[runadun1220]

The flasher is a 12pin?!?!

Just so I understand, and before I go through doing all the work I'm just trying to understand. I've previously used the the resistors to cure the hyper flash on my 2004 4runner. They worked well for awhile until the wires corroded and got semi fried because of how hot the resistors get. So I bought a new flasher for LED's but from what I've seen it's 4 pin. Are all 4th gen 12 pin flashers? I bought the flasher from super bright LED's which I thought was pretty reputable. Is it possible the number of points are different in the 2006-2009 models opposed to the 2003-2005 models, while all 4th gens to have their differences when it comes to the drl/blinker set up. I guess my question has anyone removed the flasher in 2003-2005 model to find the flasher is a 4 or maybe 3 pin I haven't really looked, or are they all 12 pin flashers? Thank for the help.

 

[thomaspuzio]

... I guess my question has anyone removed the flasher in 2003-2005 model to find the flasher is a 4 or maybe 3 pin I haven't really looked, or are they all 12 pin flashers? Thank for the help.

Don't bother. You will find a 12-pin relay and no way to swap it for an aftermarket model. The only options you have are:
1) use regular blinker bulbs, and LEDS for everything else in the truck
2) use resistors
3) Crack open the factory 12-pin relay and monkey with the metal bar in there to make it thin enough to account for the lower draw from the LED bulbs

I chose 1. All bulbs in truck are now LEDs except the blinkers. Big whoop. Everything else looks cool, and the difference in the blinkers is minimal anyway.

 

[chrisd833]

Thanks for this thread (and the one on Tacoma World). It helped me through the effort of pulling the flasher box out, removing the metal bar/loop from the circuit board, adding a bunch of resistors in parallel in its place, having the blinkers sort of work (i.e. one side only), then putting everything back the way it was with the metal loop/bar and using regular bulbs.

The problem I'm having is that now the front passenger, 2nd passenger and rear windows dont work. And the front left bulb remains on even if the car is off. The driver window does work though.

It could have something to do with these two cables that are not plugged in anywhere. After I put the fuse box back in I couldn't see anywhere to plug these.

Does anyone have any ideas on how to fix or where these cables go?

The cable with the grey connector is a lot longer than the other.

 

[nayborbob]

I have my 2003 flasher out/apart. its 12 pin, and thats because I have daytime running lights (DTRL) with my 03 Limited 4R. HTH

I just ordered the SMD resistor to replace the 201 on the board. Hope to complete over Thanksgiving holiday. Part I ordered is

P1.8KWCT-ND from Digi-Key ($0.030 each)

digikey.com/product-detail/en/panasonic-electronic-components/ERJ-12ZYJ182U/P1.8KWCT-ND/249717

 

[nayborbob]

I installed LEDs in my DTRL/front turn signal lights on my 03 4R, then discovered hyper flashing turn signals. So I replaced 201 with 182 resistor at R4 in the relay, as the first post in this thread was suggested by utmba95. Turn signals went from hyper flash to erratic, slightly less hyper flash. For me the mod at the top of this thread did not work. I think I will be going back to conventional bulbs.

 

[Ed_C]

I installed LEDs in my DTRL/front turn signal lights on my 03 4R, then discovered hyper flashing turn signals. So I replaced 201 with 182 resistor at R4 in the relay, as the first post in this thread was suggested by utmba95. Turn signals went from hyper flash to erratic, slightly less hyper flash. For me the mod at the top of this thread did not work. I think I will be going back to conventional bulbs.

Some LED replacement bulbs may work erratically if run constantly on like as a DRL.

I have Philips Xtreme Ultinon 7440 amber bulbs, still one of the best designed LED bulbs (outperforms even Philips' second generation Xtreme Ultinons). They were designed to be used only as turn signals; after 5 minutes of constant-on run time they start blinking as a form of thermal protection.