2012 Fog relay

[Absolutely Red 12]

I cant seem to find the fog relay plug.
Remember his is a 2012, all previous diagrams dont mean squat!!

BTW, my 2012 already has a fog light loom under the hood!!

[CTScott]

There is none on the 2012. The fog light relay is built into the body ECU.

To see if it is enabled on your car, you can jump pin 3 to pin 4 on the headlight switch connector D106. Pin 3 will be brown or green (depending on if you have the OEM alarm) and Pin 4 will be green.

Jump those wires and have the ignition on and the headlight switch in the low beam position. If the fogs don't light then the relay is not in there. For the 2nd gens for instance the integrated relay for the power windows and locks is not present on cars that were not built with them (and there are different part number for the body ECU).



D106.jpg

[Absolutely Red 12]

Originally Posted by CTScott

There is none on the 2012. The fog light relay is built into the body ECU.

To see if it is enabled on your car, you can jump pin 3 to pin 4 on the headlight switch connector D106. Pin 3 will be brown or green (depending on if you have the OEM alarm) and Pin 4 will be green.

Jump those wires and have the ignition on and the headlight switch in the low beam position. If the fogs don't light then the relay is not in there. For the 2nd gens for instance the integrated relay for the power windows and locks is not present on cars that were not built with them (and there are different part number for the body ECU).



Attachment 48579

CTScott

Thank you, I was getting that impression from reading the Prius C forums.

The fog harness behind the bumper is already there, as is the fog fuse.

I do not have the OEM alarm, so brown to green?
What wire is the parking light, if I cheese to not use low beam?
Is the illustration pin side, or wire side?


Again, thank you!

[CTScott]

Originally Posted by Absolutely Red 12

CTScott

Thank you, I was getting that impression from reading the Prius C forums.

The fog harness behind the bumper is already there, as is the fog fuse.

I do not have the OEM alarm, so brown to green?
What wire is the parking light, if I cheese to not use low beam?
Is the illustration pin side, or wire side?


Again, thank you!

If you have the alarm or DRLs - Green to brown.
If you have neither alarm nor DRLs - Green to Green.


The connector illustration is looking at the pin side of the connector.


For the parking light turn on, it is a bit more complicated for the 2012, as for the ones with DRLs, that functionality is built into the body ECU, so it will be completely different for DRL vs. non-DRL Yaris. I would start with seeing if it works at all on a non-factory equipped car.

[Absolutely Red 12]

Originally Posted by CTScott

If you have the alarm or DRLs - Green to brown.
If you have neither alarm nor DRLs - Green to Green.


The connector illustration is looking at the pin side of the connector.


For the parking light turn on, it is a bit more complicated for the 2012, as for the ones with DRLs, that functionality is built into the body ECU, so it will be completely different for DRL vs. non-DRL Yaris. I would start with seeing if it works at all on a non-factory equipped car.

Got it, will let you know tonight.

Thanks again!

[06yarishb]

Originally Posted by CTScott

There is none on the 2012. The fog light relay is built into the body ECU.

To see if it is enabled on your car, you can jump pin 3 to pin 4 on the headlight switch connector D106. Pin 3 will be brown or green (depending on if you have the OEM alarm) and Pin 4 will be green.

Jump those wires and have the ignition on and the headlight switch in the low beam position. If the fogs don't light then the relay is not in there. For the 2nd gens for instance the integrated relay for the power windows and locks is not present on cars that were not built with them (and there are different part number for the body ECU).



Attachment 48579

Sorry stupid question: what do you mean by jump pin 3 to pin 4? Is that mean you connect the pin 3 to pin 4? just got a 2012 yaris hb le and want to add the fog light on. Thanks

[CTScott]

Originally Posted by 06yarishb

Sorry stupid question: what do you mean by jump pin 3 to pin 4? Is that mean you connect the pin 3 to pin 4? just got a 2012 yaris hb le and want to add the fog light on. Thanks

With the 2012's to add fogs you simply install and connect the foglights on the front bumper and then install a switch that connects the wires in pins 3 and 4 together (i.e. jumps one wire to the other).

[Absolutely Red 12]

Originally Posted by 06yarishb

Sorry stupid question: what do you mean by jump pin 3 to pin 4? Is that mean you connect the pin 3 to pin 4? just got a 2012 yaris hb le and want to add the fog light on. Thanks

Remove the lower steering column cover.
Locate the connector shown in my picutre.
Tap the fog switch wires, one to the violet, and the other to the green wire.
The two by themselves.

You can alternatively not use a switch, and jump the two wires, they will go on, and stay on when the headlights are turned on.

[oohcory]

Originally Posted by Absolutely Red 12

Remove the lower steering column cover.
Locate the connector shown in my picutre.
Tap the fog switch wires, one to the violet, and the other to the green wire.
The two by themselves.

You can alternatively not use a switch, and jump the two wires, they will go on, and stay on when the headlights are turned on.

I for the life of me cannot find this. All that's below my steering column is an airbag? I'm a noob, little help please?

[CTScott]

Originally Posted by oohcory

I for the life of me cannot find this. All that's below my steering column is an airbag? I'm a noob, little help please?

You are looking too far down. You need to remove the lower steering column cover to find that connector (which is at the base of the headlight switch).

[Eforno]

Originally Posted by Absolutely Red 12

Remove the lower steering column cover.
Locate the connector shown in my picutre.
Tap the fog switch wires, one to the violet, and the other to the green wire.
The two by themselves.

You can alternatively not use a switch, and jump the two wires, they will go on, and stay on when the headlights are turned on.

I tried PMing you but it didn't work for some reason; I see no record of it in my sent inbox. I've read this entire thread and I am still confused with how the wiring works. How exactly do you jump a wire? Scott's definition is to connect it with the switch, but how do I jump it without anything, as to test if the relay is there or what not. All I can think of when it comes to jumping a wire to to slice it open and then twisting it together.

[CTScott]

Originally Posted by Eforno

I tried PMing you but it didn't work for some reason; I see no record of it in my sent inbox. I've read this entire thread and I am still confused with how the wiring works. How exactly do you jump a wire? Scott's definition is to connect it with the switch, but how do I jump it without anything, as to test if the relay is there or what not. All I can think of when it comes to jumping a wire to to slice it open and then twisting it together.

Tap Splice connectors are the easiest way. They bite through the insulation on two pieces of wire to make the connection:

[Absolutely Red 12]

Pins 3&4 are violet, and green.
Jumping them does not turn the fogs on.
Using DVOM shows no voltage coming from either wire when turning on the
headlights.

[Absolutely Red 12]

OK. DISREGARD my last post.
I forgot to turn on the ignition DOOOOHHH!

Jumping the purple and green wires at 3&4 made the fogs go on!!
The light on the dash also works!!

Time to get some taps, and wire the switch.


Now taking this one step further, how do I make it work with park, low, high.

CT Scott, thank you for the help, also in advance!!

[CTScott]

Originally Posted by Absolutely Red 12

OK. DISREGARD my last post.
I forgot to turn on the ignition DOOOOHHH!

Jumping the purple and green wires at 3&4 made the fogs go on!!
The light on the dash also works!!

Time to get some taps, and wire the switch.


Now taking this one step further, how do I make it work with park, low, high.

CT Scott, thank you for the help, also in advance!!

Do you have DRLs?

[Absolutely Red 12]

Originally Posted by CTScott

Do you have DRLs?

No DRLs.

Also now using a PIAA switch, as the cheap Chinese Toyota looking switch would not allow the fogs to turn off.

New switch is a 3 wire, internal lighting, when on. It also allows the dash icon to turn on!!

[CTScott]

Originally Posted by Absolutely Red 12

No DRLs.

Also now using a PIAA switch, as the cheap Chinese Toyota looking switch would not allow the fogs to turn off.

New switch is a 3 wire, internal lighting, when on. It also allows the dash icon to turn on!!

You should use a four, not three wire switch. The illumination should be isolated from the switching.

I just noticed that for both the DRL and non-DRL Yaris the fog relay coil is tied directly to the body ECU internally in such a way that it prevents the fogs from turning on except when it decides it is OK to. You would have to either do some surgery on the body ECU or use an external relay and rewire the fogs to it to override that behavior.

[Absolutely Red 12]

Originally Posted by CTScott

You should use a four, not three wire switch. The illumination should be isolated from the switching.

I just noticed that for both the DRL and non-DRL Yaris the fog relay coil is tied directly to the body ECU internally in such a way that it prevents the fogs from turning on except when it decides it is OK to. You would have to either do some surgery on the body ECU or use an external relay and rewire the fogs to it to override that behavior.

Ok, Ill leave it like this for now.
The Chinese switch was a four, with isolated illumination. Wouldn't allow the fogs to turn off!! The three wire works as expected, Ill get another 4 wire to avoid future issues.

Thanks a bunch.