LED DRL bulb replacement with stock DRL flasher and NO RESISTORS!

I'm interested in switchbacks for my 2012 prerunner with dtrls. I was ready to buy, but didn't like the resister thing using up the equivalent power as if it was still the 4157nak bulbs in dtrl mode. and getting hot and giving the dealer a reason to notice a mod with the truck under warranty....
But how about putting the load resistors behind the rear light housings; tie into the rear amber turn signal [only] bulbs and the resistor should only have to work during the turn signal mode.... I figure it's the same circuit, right? and resistors wouldn't get hot... (or am I missing something-apologies if someone's already posted this...)
For that matter, get a couple spare light sockets with pigtails and wire them instead of resistors; let them 'blink' behind the tail light where no one would see them-[po' boy resistors] make the circuit think the front bulbs are still there....
Oh another idea....what if the rear amber bulbs,

$38 3157a /4157A ST BP SilverStar 27-Watt High Performance Signal Light

3157a, are switched for the 4157nak bulbs, AND the filaments wired together. The 4157 draws more power and if both low and high filaments are wired together so both flash, wouldn't that maybe add enough wattage to fool the stock flasher unit?

 

Hey JGraham, great mod man. I was wondering when will we see the write-up for this. I imagine you may have more important things to do, but such a fine work will be much appreciated for us normal mortals.

 

I did the led mod this weekend while replacing my melted factory housing. I ground down the resistor as jgraham told and it works and looks great!

 

What about this, this one is for 4 led positions, both front and back..they have a 2 led flasher, front or back.

http://www.v-leds.com/Electronic-Flashers/TOYOTA-ELECTRONIC-4-LED-p4481146.html#ReviewsTabAnchor

 

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Hey guys. Finally finagled the time to do this mod.

I used LEDs from www.superbrightleds.com for my '10 DCLB Taco. You do need the CK option for the fronts bulbs. I replaced the DRLs, side markers, and rear directionals. I have LEDs inside the cab and in the third brake light (just have the reverse lights to get next - probably this week.)

The issue I have run into is that I have finally ground enough away of the resister loop to have the lights not hyperflash, however after about 35 flashes the directional automatically shuts off - I think it just gets too hot and shuts down.

I too ground through the loop a couple times, thank God for the soldering iron though.

It took about an hour to get to the point of having it not hyperflash, and I will have to tweak it a bit more so that it does not automatically shut off.

Incidentally, while replacing the front bulbs in the DRL I noticed that the bulb housings had just started to brown up as though the housing and bulb insert had been getting quite hot. Looks like I got the mod done just about in time so I did not have to replace the entire lamp assembly.

The LEDs are not quite as bright as the OEM Sylvania bulbs, but I think the lighting looks better in general. I will know how it looks next week when I get back to work and drive home at night.

Thanks to the original poster as well. Even with the magic of Google there does not seem to be a 12-pin LED flasher out there.

 

You are bang on with the location of the flasher relay on the 012's. I recently added a factory tow hitch electrical harness which came with a blue flasher relay that had to be put in place of the original one which is black. Btw, the factory tow harness only works if the truck has DRL's, at least for a 2.7 base, which tells me that non DRL Tacos may have different flasher relays. I don't know for sure why one cannot use a factory tow harness without DRL's. What I wonder is if extra or excessive heat is generated inside the relay with this mod and if the extra heat makes any difference overall.

 

this is 100% confirmed working. took off ~25% for 2 rear led turn signals

 

Thank you for posting this! I was all set to mod my flasher unit (based on some tutorials I'd seen) and then came to find out that because I have a '12 with DTRL, I had a totally different module. Good to know it's still got some grindable / replaceable shunts. I'll try to take pictures when I do mine and post 'em back here.

 

Calculation example:
I want to calculate the correct replacement shunt resistor value.

The current used to provide power to the front & rear signal light flows through the shunt resistor in the flasher's circuit. The current flowing through the resistor provides a voltage level that is measured by the flasher's circuit. The more current flow through the resistor, the larger the voltage measurement.

The flasher circuit measured voltage needs to be at least 0.049Volts. If it is less than that, the flasher does the hyper-flash output.

The spec for the LED bulbs I intend to use for the signal lights show 490mA for the front, and 340mA for the back = 830mA. If I want the hyper-flash to let me know when a bulb is not working, then I should calculate a resistor value to provide greater than 49mV at approx. 500mA (0.5Amp) The resistor value should be 0.049V / 0.5A =
0.098 Ohm. Best match would be 0.1 Ohm (100 milliOhm).

Next post will look at what power the resistor should be able to handle.

 

Calculation example: Power rating for the flasher's shunt resistor.

The one challenge from the example above is that I do use my truck for towing.
Adding a normal incandescent bulb to the flash circuit = 27W.
27Watts/12Volt = 2.25Amp . Add that to my LED load from the above post example = 3.08 Amp.

The 3 Amp load is passing through my new resistor value of 0.1 Ohm. The power, in the form of heat this produces = square of the Amps x Resistance value.
3A x 3A x 0.1 Ohm = 0.9W The 0.1 Ohm resistor needs to have a power rating of at least 1 Watt. I know from experience, that for long trouble free service life I should double this and use a 2 Watt resistor.

So now I know I need a (2005-2010 DRL) , 0.1Ohm 2 Watt resistors for my flasher mod.
You can check out mail order supply houses such as mouser electronics or digikey.
example:
http://www.digikey.ca/product-detail...0CT-ND/2021752

 

Hey all. Just did this mod using resistors in place of the factory shunt for a 2009 Taco with LED DRLS and incandescent rear turn signals. A single 0.10 ohm resistor in place of the factory shunt allowed the turn signals to work but not the emergency flashers. I placed two 0.10 ohm resistors in parallel for a resistance of 0.05 ohms and presto, both the turn signals and emergency flashers work.

 

Any pics??

 

Can't you just get a new Tacoma LED RELAY and just install the LED, and your good? Seems like a no hassle option for 13 bucks?

http://www.superbrightleds.com/more.../fl2-red-led-bulb-electronic-flasher/779/833/


Description
Electronic LED Flashers have no minimum load-12VDC. Eliminates the need for load resistors, turn signals will flash at normal rate with or without LED bulbs.

 

That one won't work with the DRL harness. That one is an 8-pin for non-DRL Toyota/Lexus. We need the 12-pin for DRL trucks.

 

Gotcha. Thanks!

 

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just cuz