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

Ok I ground down the shunt and it fixed the hyperflash but now the DRL function is gone. What the heck did I do wrong? I even added some solder back on the shunt and got the hyperflash back but no DRL. Suggestions???

 

I got it figured out, not sure what exactly was wrong though. I re-soldered the shunt and plugged the flasher back in and at first still no DRL. I noticed that while taking the panels off I had pushed in the E-brake so I released it, that didn't seem to work either. So I started up the truck and put it in reverse then drive, after that everything seemed to work so I left the truck running and pulled the flasher and started back to grinding on the shunt. Grind a little, plug it in, check turn signals, and repeat until flash rate is right. Now everything seems to be working correctly. Thanks to the OP for figuring this one out, I didn't really want to splice resistors into the harness and this worked out perfect.

 

The DTRLs don't come on if the parking brake is set, and the truck isn't yet in drive. Maybe somewhere along the way the flasher unit got confused and thought that was the case? Either way, cool you got it working!

 

Did my mod to adapt DRL flasher, but removed the shunt (piece of metal loop that the OP grinds down) with replacement resistors of the right value.
One of the bigger PIA parts was removing the flasher module on the side of the fuse panel.

Remove the harness connector to the flasher. (push in the connector tab at the center of the connector.)

Remove the flasher by pushing up hard from from where the wire connector plugged in. The sucker slides onto the side of the fuse block from top. It took me a bit of fiddling to find this, expecting to find a locking mechanism/tab to hold it in place, but that was not the case. It does need a fair bit of force to push it up.

& thanks to Rich for the pictures at the top level of this thread http://www.tacomaworld.com/forum/technical-chat/1475-05-drl-daytime-running-lights-install-oem.html to see how to access the Flasher.

 

Here's a pic of the mod installed.


Added two 0.22Ohm resistors in parallel to provide a shunt resistance of 0.11Ohm
re-measured the Vdrop across the resistor while operating with LED lights to compare to stock bulbs & stock shunt resistor.

Stock - 75mV drop, single side flashing
After mod - 123mV drop single side flashing.

looks like I can drop the resistance some more, so i'll be adding another .22 ohm resistor in parallel (because that is what I have available), to bring the value down to .073Ohm. Ideally I'd want to have .067Ohm to mimic the stock operation, but this will be plenty close enough, and still avoid hyperflash.

Now to try to hook up regular trailer lights, and see what happens. I suspect it may not work properly,leaving me to put in relays to operate the trailer lights. Oh Well.

 

..and confirmed. Current for trailer lights does not flow through flasher relay. Towing Converter Relay manages that, so no problems or impact to flasher unit. Yea!

 

Could you in theory add the resistor to the shunt without removing it or will that not function properly due to the properties/principals of electrisity?

 

^^^ If you mean leave the shunt in place, and add resistors across it; No, this would further decrease the resistance.

Stock resistance is 0.020 Ohms; for my application I need to increase the resistance to 0.070 Ohms.

What I could have done is cut out the center portion of the stock resistor, and add my new ones across the legs sticking up. I decided to completely remove the stock resistor, and solder the new ones in its place.

 

Makes sense, thanks. I may try this on my Tundra, it has the same flasher as the Tacoma. I used the grind down method on the DRL flasher in the Tacoma.

 

What's the wattage on those resistors? They look to be around 1?

 

^^^ Resistors are 2Watt rating each.

 

so...same thing happened to me, except when i tried those things, it didn't fix it...any ideas?

 

aaaaaannnnd, i'm an idiot...fuse blew. couldn't find the dumb thing...

 

that little bugger! took me an hour or more to get that dumb thing off! But there's a close up (from the bottom as it is installed) of the flasher unit case. do you just have to stick a close hanger (that's what i used) or something like that up there to lift that little latch so you can slide it up and off the rail.

found out my issue was i put the led in backward so it popped the fuse. did it again on the passenger light and as soon as i hit the turn signal it popped again. flipped the thing around and it's been good so far.
i let it run blinking for almost a minute to make sure and to make sure i took off enough material. for whatever reason the passenger side required more to be taken off. thought that was weird. anyway, thanks a ton for this! lovin' the look.

 

Thank you all for this thread! Thanks to jgraham and your smarts, this was a lot easier than I expected. The hardest part was getting the relay off the fuse panel and the housing apart. I was able to get it all done in under an hour and so far all's holding up and there are no more melting DRL lenses.

I found that grinding the top of the resistor loop with slow RPMs and very slight pressure as thin as I felt comfortable before breaking through then moving to the side of the loop worked well and kept the resistor intact. I'll be sure to share if and when I have to eat my words and come crawling back for more info.

 

Nice mod. I think I'm going to buy a new flasher relay to mod just incase I remove my LEDs or if I mess up the mod.

 

Are you running 2 or 4 LED signal lights with this?

 

Four, replaced both front and back signal lights. The resistor value required will depend on the current draw of your LED replacement bulbs. I can help you with that calculation if you like.

Rob

 

Defiantly any help will be appreciated, currently I have replaced my front signal / DTRLs with switchback LEDs, which I’m having trouble with, trying to get the switchback feature to work. But I’m looking to replace my rear signal lights and front when it’s all over, so I will need to mod the relay. If I can’t get the switchbacks to work I’m just going to replace all 4 with regular CK 3157 amber LED lights. When I get there I’ll shoot you a PM with the draw of the LEDs used. How many and what size resistors should I solder in place in general for standard LED lights or are they all slightly different?

 

many slightly different. i know what a pain it is to get the flasher out of there, so in my mind, working with the correct info, and only having to do the mod once is preferable.