[Zykrus]

Hi,
I have Defi Racer gauges in the a piller.
Right now I run my tail and marker lights all the time + my fogs. Given how the factory illumination system works the gauges and radio dim when the headlight switch is moved from off to marker lights and is still dimmed when I switch to headlights.

I would like to change this so the dimming only occurs when the the headlights are on.

I have a full wiring diagram but I can't seem to find exactly what I need to do this.

What I would like to do is roll the illumination roller switch to the first notch down which currently dims when the headlight switch is moved from off to marker lights. This end the end this would be changed to when the switch is moved from running lights to headlights.

I hope I was able to explain this well enough. It seems like a minor deal but having constantly dimmed gauges and radio gets annoying during the bright/sunny days.

 

[1 Lucky Texan]

you may need to find a gadget called the Illumination Module

but I'm not certain

 

[miker104]

That could be easy or could be very difficult. As Tex says that is controlled by the Illumination Control Module. I'm not sure how complicated rewiring that would be but start with the Wiring Diagram for the Illumination Control Module, will probably involve the light switch as well (internal signals to the ICM).

 

[Zykrus]

Thanks for the tips.


After combing through the wiring diagrams more I think I found what I need and it appears to be super simple. It looks like I need to take the illumination wire from the headlight control stick that connects to the marker / tail lights and splice it into the headlight wire instead.


I'm going to try this when I have some time later this week and I'll update this thread.

 

[RoughDiamond]

It looks like I need to take the illumination wire from the headlight control stick that connects to the marker / tail lights and splice it into the headlight wire instead.

It should be this simple. The illum. module only kicks in once it sees a "trigger" signal (and from the keyless entry as well). Your simplest method is to probably tap into the harness connector at the column bundle under the kick panel. I think a de-pin and vampire tap would be easiest and least "permanent".

 

[plain OM]

. . . After combing through the wiring diagrams more I think I found what I need and it appears to be super simple. It looks like I need to take the illumination wire from the headlight control stick that connects to the marker / tail lights and splice it into the headlight wire instead. . . . I'm going to try this when I have some time later this week and I'll update this thread.

Which of the two cars is the subject here?

Be interested in learning which wire this is, and where it would be moved, based on the wiring diagrams. I've looked at the diagrams for both the 08 and 06. The brightness of the combination meter and the dashboard switches etc., is controlled by the Body Integrated Unit (there's no separate illumination control module as on earlier generations), but I haven't found any connection to it that would allow the external clearance and tail lights (aka parking lights) to be on with the headlight switch at the first position (parking lights), without also causing the BIU to set the dash brightness according to the variable brightness control's position, which presumably is not at the full bright position.

 

[Zykrus]

which of the two cars is the subject here?

Be interested in learning which wire this is, and where it would be moved, based on the wiring diagrams. I've looked at the diagrams for both the 08 and 06. The brightness of the combination meter and the dashboard switches etc., is controlled by the body integrated unit (there's no separate illumination control module as on earlier generations), but i haven't found any connection to it that would allow the external clearance and tail lights (aka parking lights) to be on with the headlight switch at the first position (parking lights), without also causing the biu to set the dash brightness according to the variable brightness control's position, which presumably is not at the full bright position.

08 OBXT. I'll update this thread when I test my hypothesis.

 

[Zykrus]

Well boooooo!

My mod did "work," but it turns out I overlooked an important detail. Subaru decided to have both the the running/taillights and the illumination circuit tied into the same relay. Given this I could not have the running/taillights on without the headlights being on if I had kept my mod.

I'm sure there's still a solution for this, but it's not a one wire change so I'll need to give it more thought.

One possible solution is to rewire the parking light switch on top of the steering column to keep the parking lights on whenever the car is on. I never use this switch anyway, but I would still like a more ideal option.