I have an 04 WRX and my fogs keep burning out. I am super super careful about replacing them. Never touch them. And I have sealed the housings with grease to help eliminate any possible water intrusion. The bulbs last for about two months and then one or the other goes out.

I have done the DRL mod so that they are off when I am driving with the parking lights on, and so that the fogs are on whenever the parking lights are on.

Any ideas? I have used PIAA bulbs and more recently Sylvania bulbs. The blueish nice ones. Can't remember their name now.

Anyway, grrrr. Please help with ideas. My only theory is that with the headlights off, the fogs are getting too much juice during normal driving which shortens their life.

 

So, you're driving around with the fogs on all the time at night? That's one reason they aren't lasting as long as you would like. Also, those "bluish nice bulbs" aren't known for long life, the filaments are overdriven to produce sufficient light output through the blue coating.
Are you using stock wattage bulbs, or higher? Higher wattage bulbs will have a much shorter life than stock ones.
The longest-lasting bulbs will be OEM type 55W bulbs with no coating.

 

I've had coated bulbs in my fogs for three years no problems.

My friend had PIAAs in his fogs..they were awesome, but yea, they burn out pretty quick. But I would think it has more to do with that whole DRL thing you did.

 

Yeah, they are the stock wattage. And I can't drive around with the stock bulbs. I'm sorry but the puke yellow color is too much for me. I'm a photographer so I pay close attention to the color of light.

Anyway, thanks for your opinions. Anyone else have any ideas?? I'm wondering if I can put a resistor in the line to help control power spikes when starting the car which might reduce the life of the bulbs. I can't imagine I am the only person with this problem. The DRL mod is pretty common.

 

This has nothing to do with the DRLs.
Adding a resistor is not a practical idea due to the high current involved, and this would also reduce the brightness of the lights.
You mention that you have the lights turned on when starting, that is a factor. You should have them off when starting then turn them on once the engine is running.
You can also check the system voltage to see if there is a problem with the regulator. Voltage at the battery with the engine running should not exceed about 14.5 volts with the engine at operating temperature. If it's significantly higher you may see premature bulb failure. The fix for a bad regulator is a new alternator since that's where the regulator is.