Diode Dynamics Fog Light Help - PLEASE HELP

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graybaker

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San Francisco, California, United States
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Gray
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Hello all,

I recently installed a set of diode dynamics fog lights on my 2018 Subaru Forester 2.5i. Boy oh boy was it difficult. Not only did Subaru not include any fog light housing for my car, but there was no switch in the dashboard or relay in the car for the lights. I went to my local Subaru dealer, bought fog light housing, a fog light switch, and two fog light relays.

I installed the housing and placed the fog lights in them, hooked them up with the factory wiring, cut out a hole in my dash to fit the switch in, and put the relays into place. The fog lights turn on... but only stay on if I hold down the switch button. They won't stay on if I release the button. This is with headlights on low-beam. The fog lights still don't turn on when my headlights, day-time lights, or high-beams are on (by design).

If anybody knows what is causing this, please, PLEASE let me know.

Thanks.
 

Conner Hunt

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Hello all,

I recently installed a set of diode dynamics fog lights on my 2018 Subaru Forester 2.5i. Boy oh boy was it difficult. Not only did Subaru not include any fog light housing for my car, but there was no switch in the dashboard or relay in the car for the lights. I went to my local Subaru dealer, bought fog light housing, a fog light switch, and two fog light relays.

I installed the housing and placed the fog lights in them, hooked them up with the factory wiring, cut out a hole in my dash to fit the switch in, and put the relays into place. The fog lights turn on... but only stay on if I hold down the switch button. They won't stay on if I release the button. This is with headlights on low-beam. The fog lights still don't turn on when my headlights, day-time lights, or high-beams are on (by design).

If anybody knows what is causing this, please, PLEASE let me know.

Thanks.
What switch are you using?
 
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graybaker

Rank III

Advocate I

778
San Francisco, California, United States
First Name
Gray
Last Name
Baker
Hello all,

I recently installed a set of diode dynamics fog lights on my 2018 Subaru Forester 2.5i. Boy oh boy was it difficult. Not only did Subaru not include any fog light housing for my car, but there was no switch in the dashboard or relay in the car for the lights. I went to my local Subaru dealer, bought fog light housing, a fog light switch, and two fog light relays.

I installed the housing and placed the fog lights in them, hooked them up with the factory wiring, cut out a hole in my dash to fit the switch in, and put the relays into place. The fog lights turn on... but only stay on if I hold down the switch button. They won't stay on if I release the button. This is with headlights on low-beam. The fog lights still don't turn on when my headlights, day-time lights, or high-beams are on (by design).

If anybody knows what is causing this, please, PLEASE let me know.

Thanks.
What switch are you using?
The factory SRF fog switch
 

smritte

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First off, I don't work for Subaru, I worked for GM. What your dealing with (electronic issues) was my specialty and I have dealt with things like this quite a bit. I can only guess based on what your posting. To do this properly, you need a wiring diagram.

Lets cover basics just to make sure were on the same page.

The lights work correctly "only if" you hold the button down?

If this is correct, you have a momentary contact switch. In order to have this type of switch work, some things need to happen.
My thoughts

1. The switch is designed for a diffrent application or vehicle (don't care if it fits). When I see things controlled like this, the switch tells a computer to turn on the relay. For the switch to control the relay, you need a standard type not a momentary contact.

2. The switch is correct and the relay type is wrong. That would mean you need a latching relay. these are almost never used in cars (don't say cant happen)

3. You plugged something in wrong. The switch may have 2 outputs, momentary and constant. The momentary may go to a computer to turn on a dash light or something.

The issue you have here is, at the dealer its all "year make model". The only way someone will be able to help you is if they actually had this issue and actually knew how it worked. Both are rare. Its more than possible your vehicle wont work with that switch. I don't care if the part guy said it would. Sometimes diffrent accessories need certain pieces installed from the factory, but you car wasn't equipped and the factory didn't include that part.

Best possible fix would be to test the switch outputs and see if you can use a diffrent pin. Next take's a bit of skill, take the switch apart and remove the momentary part making it a standard switch. last would be run an aftermarket switch.

All three suggestions I have done on multiple vehicles, all of which I had a diagram for. I almost always use factory switch's, some of which I repurpose to control different things.