Electrical Mods, Fog install and LED Flasher

Two things I want for the 2010 Grade are Fog Lights and a programmable flasher relay in prep for all LED running lights.

Step one, I want control of the fog lights so, I am not installing the OEM stalk, rather a fleabay fog light switch. Upon review of the trucks electrical, it needs an active low at the relay in the engine fuse box (Signal to Ground). This switch, is an active high (+12V).
I opened the switch and drew a quick schematic which led to cutting two traces and adding three mod wires. The OEM fog light relay measures 164 ohms so, 14V / 164 ohms = 86mA which the small mod wire will be fine with.

The switch had two +12V inputs, one to light it and when the switch is on, the other illuminated "switch is On" and output +12V on a blue wire.

Here is the simple fix.


NOTE: Switch contacts A-B = Off Position. B-C = On Position.

Once reconfigured:
Black = Ground
Red = +12V (on w/ignition on)
Blue = Active low Ground
Yellow = unused (was +12v in to power blue wire out)



Edit: Plans changed! I ran my active low switch output to the Grey Wire formerly plugged into junction AJ12 pin#8 which goes to the fog light relay in the engine bay fuse box. Problem solved as no extra wire is needed.

The next step is a power tap in the drivers side fuse panel to power the switch (5Amp), Ground the switch and run a wire forward to the OEM relay and intercept Pin #8 leaving the Body ECU out of the picture. Future state is, Key on powers the switch and if the lights are on in any position this enables the relay turning the fog lights on.

Fog lights are Morimoto XB LED fogs which I have but I'm missing the adjuster screw to install them.
-sigh-

Edit#2 I bought some used fogs off fleabay just for the adjusters.

 

I assume your truck did not come with the OEM stalk from factory? I posted this idea a few weeks back if someone ever wanted full control of the Fogs with the Factory Stalk it can be done by moving around some wires on both sides of the relay pretty easily.

You would have to join the Pink FFOG wire to the Sky Blue FFGO wire at the Body Control Module. Doing so bypasses the Body Control Module restrictions on fogs being turned off when the bights come on. This makes the low signal from the OEM switch be directly connected to the relay. Removes the body control module acting as a middleman.

Second step is take the Green Power wire to the Relay and run it to a key on 12V power source. The makes the relay "hot" as soon as the key is on instead of the factory wiring where the relay is only powered when the headlights/tailights come on.

Doing both of these simple mods would allow you to turn on/off the fogs with the factory switch any time the key is on. When the key goes off, the relay should loose power turning the fogs off and meaning you can "forget" and leave the switch on all the time.

 

I'm still looking for input on this topic; what is the PN for the fog light adjuster mechanism?

https://www.tundras.com/threads/what-am-i-missing-fog-light-adjuster-pn.122322/

I can only imagine these get broke all the time in fender benders. Do they only come with new fog light assemblies? I bought the buckets new and they didn't come with them.

 

Jeff,
Thanks!
That is correct, my turn stalk does not have Fog light switch. I know it's only $120... Which, I may end up regretting that about the time I try to run a wire out of the cab vs pulling the wheel and adding OEM stalk and the Mod listed here.
Honestly, that looks like a nice clean easy sweep that no one would notice vs what I'm about to do. lol

Question about Flasher Relay and DRL Light vs no DRL light.

The difference between the Flasher Relays appears to add FET 3 and FET 4 which power parts of the tow package. Then one has to wonder what all that IC is doing to with the Tow Package integration vs DRL? My plan is to integrate a Diode Dynamics CF18 programmable flasher relay into the TT eliminating the need to add ballast resistors and all that jazz.



Shown is the flasher module with DRL lights PN 81980-0C020


Edit: upon pulling my relay module, I was wrong and mine is none - DRL so FETs 1 and 2 are not on the PCBA.

 

FWIW: Testing the circuit board was done with a 9V battery and DMM. While I was at it, I was surprised to see the little 9V bat could kick on the Morimoto XB LED. Definitely not to full potential but enough to let you know it works.

Here is the housing... It appears each has just 3 LED's inside and shoot into curved aperture and produce a rectangular output.

 

This is what I have...

Seems to me Pin 1,3 power (Red), Pin 6,7 are inputs from turn signal stalk (Blue), Pin 12 Hazzard input, Pin 4 Ground

Pins 2,8 are the traditional blinker signal to the taillights, mirrors, cluster ect. AND from what I see 10,17 (Green) are DRL/Blinker on the front headlights only. Seems this was split up to keep the front "blinkers" on at a dimmer non flashing state for the DRL. That is why you need the sperate 10,17 circuit for the front headlights/blinkers.

Pin 5 (Green) is some kind on DRL control from the Body Control module, could be a simple DIM signal to DRL when headlights come on.

Pin 11,16 (Yellow) are power and input for Towing/Brake switch. Pins 9,18 (Yellow) are just wiring to the trailer socket for towing. I would assume instead of tying into the tail signals they just wired trailer towing signal directly to the flasher relay.

Could the IC be the brain for DRL control? On bright during day, flashing when blinker comes on, on dim with headlights ect.

 

Baby steps. Hardware installed and a jumper across the relay brings light.

Now I need control from the cabin!

 

While looking for the Body ECU (BCU) location and other components, I found this parts locator. Its for 2009 but still good content for anyone wondering where stuff is. It's 62 pages of pictures, diagrams and details about where sensor, connections, computers are located.

It could be on this site too but I didn't easily find it. from the Yoda gods.

tag: gen2 #electrical component location

Back to the topic at hand, I need to better understand what the logic on the OEM flasher relay is really doing. Thank you for you insight on this about the DRL/Fog and all of that. Much appreciated!

 

@Jeff_5_7
I set out to do hybrid rewire job using part of your idea and part of my idea a non-oem switch for the fog lights but none our wire colors map correctly to connector AJ10 pin 8 or connector H4 pin4 of the BCU.

Any thoughts? I know the flasher relay diagram you posted had some different colors than mine, and what I have came from ALLDATADIY.COM and verified it against Toyota documents for my 2010. Is this common for colors to change?

Here is what I believe to be AJ10.


Thanks!

Also, to add insult to injury the flasher relay I posted up there is not the one in my truck. Mine has no DRL so it's two relays, two FETs. 81980-0C020 which actually simplifies my flasher project.

 

PS I have some none OEM fog lights and buckets left and right for a chrome bumper if someone wants them. They'll be cheap. Shipping could cost as much.

You have to find these little adjusters to use them.

 

This is what Toyota has for the 2010.

AJ10 Left and AJ2 Right are the two junctions I see called out.

 

Found the little bugger last night. It was right there in plain sight. I'm not sure what my malfunction was.

For anyone else taking the cautious path, here is what I did.

With AJ10 unplugged:
1) Using a DMM with negative on ground, verify no power is present at pins 1 and 2 of engine bay fog light relay. Repeat test using ohms setting.

2) Using a 12V incandescent test lamp, attach one side to ground, the other to the grey wire of AJ10 pin 8.

3) Look for state change at fuse box relay pin 1 using dmm. Resistance showed .6 ohms. Remove test lamp in step #2, repeat. Grey wire verified.

4) Installed relay, turn on running lights, repeat step #2. Fog lights are on! And ya, the current through the test lamp does light it. It's cheap insurance when not 101% sure everything is okay that no wires, fuses, or other items of interest will be damaged.

 

Adding this to a thread I watch...

My only dig against my new fog light switch is the brightness is far greater than OEM switch next to it.

Time for a resistor swap to dim it down.



The elusive grey wire tamed w crimp and shrink tube.


Best tool ever. Had this for over 30 years.


Done...


Edit - I lied. Second dig is my Bussman piggyback fuse holder used to power switch LEDs keep me from installing the fusebox lid. The piggyback has a plug on it so, maybe I find another power source as there are several unused plugs under the dash and switch only needs to power the LED lights inside. One could be used for such a cause once identified.