Background: 2009 G37S coupe, just acquired 5 weeks ago. Turned on the fog lights and wasn't crazy about the look compared to HIDs. Bought "city light" replacements and COB12 fog light replacements from Diode Dynamics. Installed them from the top since I had already pulled the stock airboxes to swap intakes. First off huge pain in the A$$ to swap the fogs (worse than any other car I have worked on). End result, city lights look great, fogs won't light. Hmmm. Ok, found the fuse box next to the battery pulled the fuse, looked ok, replaced anyway, no change. Swapped back in stock bulbs that worked originally now not so much.
Any ideas what I did wrong? I'm swapped exhaust, intakes, gtr start button, all interior lights including glove box, and this is the thing that has stopped me in my tracks.
Thanks for any suggestions. -Josh

 

"worked originally now not so much." Do you mean they don't work at all now or are they intermintant? LED's are sensitive to polarity so when you plug any LED in and they don't work, swap them around.

 

Sorry, meant that the original fog lights (halogen) worked before swapping out with leds, but now after putting the OEM bulbs back in they don't work. Before I inserted the LED bulbs in the housings I tried rotating them since they wouldn't light. Replaced the fuse since I thought that might be causing the problem, but nothing.
Bulb: 2008-2010 Infiniti G37 Coupe Fog Light LEDs (pair) ColorCool White (6000K)Bulb ModelCOB12 (86 lumens)2xH1_COB12W1
http://www.diodedynamics.com/store/c.../view/id/2757/
Do the fog light bulbs have to be installed in the housing to light? Wondering if they need to be installed for ground to work?
Are the fogs linked in a circuit? (wrong terminology) If one bulb is out will the other not light?
Pretty sure this is something easy but for the life of me I'm out of ideas.
thanks Josh

 

Sounds like you had the polarity incorrect for the fog lights. If you rotate the plug 180* degrees and reinstall the bulb, it should work perfectly.

The COB12's do require a specific polarity

Nick C.

 

But the OE halogens don't.
The OP states they don't work either!!

OP:
Is the foglight switch on the headlight stalk ON?
They don't work when high beams on, either, so check that too.

 

When I replaced my halogen fogs with LEDs, they acted funny for a few minutes. One would turn on fine but then turn off after several seconds, then come back on. I then switched the lights on and off a bunch of times and eventually it stayed on. Then when I installed the next one, it wouldn't turn on at all. I tried switching them on and off again and after a few tries, both the lights worked just fine. I know it doesn't sound logical, but it felt as if the car was learning there were new lights and was getting used to sending the right amount of energy to keep them on. I wonder if the ECU has anything to do with it. Will an ECU reset help?