Fog light mod and keep CAN bus Dash Light DPDT Relay

[mugenrios2k]

After looking through multiple FOG light mod threads including
ANTMAN'S and others


Wonder why no one had suggested a double throw double pole relay.


Any one know the exact logic of the Stock ECU to know when to turn on the Fog light indicator on the dash via can bus from the ECU.

1) just based on the switched ground signal from the OEM Fog light switch ( and headlights on)

2) or based on pin/wire 13 going positive ( see diagram where I have it marked cut) and headlights on


If its just #1 then the below diagram will get you fog on with hi beams and still retain the can bus dash light as on when in low beam.

If its #2 then not cutting wire/pin 13 could potentially keep Fog light indicator in the dash lit not only in low beam mode but possible hi beam mode as well...

 

[JP421]

After looking through multiple FOG light mod threads including
ANTMAN'S and others


Wonder why no one had suggested a double throw double pole relay.


Any one know the exact logic of the Stock ECU to know when to turn on the Fog light indicator on the dash via can bus from the ECU.

1) just based on the switched ground signal from the OEM Fog light switch ( and headlights on)

2) or based on pin/wire 13 going positive ( see diagram where I have it marked cut) and headlights on


If its just #1 then the below diagram will get you fog on with hi beams and still retain the can bus dash light as on when in low beam.

If its #2 then not cutting wire/pin 13 could potentially keep Fog light indicator in the dash lit not only in low beam mode but possible hi beam mode as well...

What?

 

[Friggin Idiot]

I'm too tired to try and figure out if this would work, but initial impression is that you're adding a relay in order to get the fog lights to come on only when the headlights are on (either high or low)?
Also you realize what it takes to get at that wire (Body ECU 13) right? Basically means removing the Body ECU from the dash which isn't easy or quick. I did it for my DRL Toggle Mod. Honestly you'd get it done more quickly and simpler with Antman's Mod, plus be able to run with out headlights. Besides do you really need the fog light LED on the dash if you can see/feel the switch? When you can't see/feel the switch easily, it's probably dark enough that you'll see the fog lights!

 

[Daikon]

I just got BD plug and play fog lights. :lol:

 

[aceee]

I just got BD plug and play fog lights. :lol:

What do your bd fogs have to do with anything in this thread? OP is talking about the anytime fog light mod where you can turn on your fogs without needing to have your low beams on. When you do that mod, the fog light indicator on your cluster doesn't work anymore.

 

[mugenrios2k]

I'm too tired to try and figure out if this would work, but initial impression is that you're adding a relay in order to get the fog lights to come on only when the headlights are on (either high or low)?
Also you realize what it takes to get at that wire (Body ECU 13) right? Basically means removing the Body ECU from the dash which isn't easy or quick. I did it for my DRL Toggle Mod. Honestly you'd get it done more quickly and simpler with Antman's Mod, plus be able to run with out headlights. Besides do you really need the fog light LED on the dash if you can see/feel the switch? When you can't see/feel the switch easily, it's probably dark enough that you'll see the fog lights!

No dont really need the can bus light on the dash but was think if it was a simple as adding a DPDT relay than why not...

I was wondering if that BODY ecu 13 was internal/ tracer to a circuit board:frusty:

 

[Daikon]

What do your bd fogs have to do with anything in this thread? OP is talking about the anytime fog light mod where you can turn on your fogs without needing to have your low beams on. When you do that mod, the fog light indicator on your cluster doesn't work anymore.

oops.

 

[mugenrios2k]

Used a Single DPDT ( double pole double throw relay) and was able to have

fog light on with parking lights ( no fog dash indicator),
Auto mode and low beam Fogs on ( WITH fog dash indicator)
Hi beam +Low+ fogs ( no fog dash indicator)

Also fogs remain off with Auto/DRL mode unless auto switches over to low beams on then the fogs come on as well ( with fog light switch in the on position) .

So from the prospective of dash indicators keeps stock indicator conditions and fog light switch still operates like stock with added functionality for other headlight modes

Also as a fail safe if you leave your headlights on or in parking light mode after parking; the Stock ECU time out still works turning off ALL LIGHTs after time out....
You still have all lights continuous on after shut down if you cycle headlight switch after shutdown.

 

[262T4Runner]

Used a Single DPDT ( double pole double throw relay) and was able to have

fog light on with parking lights ( no fog dash indicator),
Auto mode and low beam Fogs on ( WITH fog dash indicator)
Hi beam +Low+ fogs ( no fog dash indicator)

Also fogs remain off with Auto/DRL mode unless auto switches over to low beams on then the fogs come on as well ( with fog light switch in the on position) .

So from the prospective of dash indicators keeps stock indicator conditions and fog light switch still operates like stock with added functionality for other headlight modes

Also as a fail safe if you leave your headlights on or in parking light mode after parking; the Stock ECU time out still works turning off ALL LIGHTs after time out....
You still have all lights continuous on after shut down if you cycle headlight switch after shutdown.

[MENTION=109752]mugenrios2k[/MENTION] That great. I would like to do this too. Can you tell me exectly where in the vehicle and the color code of the wire you tapped the DPDT relay into?

Thanks

 

[HanginInUtah]

Besides do you really need the fog light LED on the dash if you can see/feel the switch? When you can't see/feel the switch easily, it's probably dark enough that you'll see the fog lights!

You're right. But... IF you can make it work like it's a factory thing (dash light comes on whenever the lights are on) then you've won the challenge of 'how did they do that?' :thumb:

This is on my list of mod's (the way Antman did it) but I've always wondered if there was a way to make the dash indicator work this way, too. So, I'll be over here watching...

 

[mugenrios2k]

There is the digram of the wire setup to make this work...
Reminder this setup requires that at least the parking lights to be switched to on

This is NOT FOG light on at any time.


To find the correct wires I used a test probe to find the +12V switched coming from the dimmer dial. ( blue doubled dashed line)

and the same probe to figure out the wire coming out of the ECU that is the power supply to the fog lights ( dashed red line)

 

[Saarlorlux]

There is the digram of the wire setup to make this work...
Reminder this setup requires that at least the parking lights to be switched to on

This is NOT FOG light on at any time.


To find the correct wires I used a test probe to find the +12V switched coming from the dimmer dial. ( blue doubled dashed line)

and the same probe to figure out the wire coming out of the ECU that is the power supply to the fog lights ( dashed red line)

Could you please tell me where "TO Original ECU Input" should I connect?