I THINK I might have figured out why our fog lights are failing........

Having broken both of my fog lights, I was able to find a new pair at a salvage yard.

After installing the new assemblies Friday after work, I was quite surprised Saturday evening, when I noticed in the reflection of a car in front of me, one of them was already out.

Sunday afternoon, I was able to take a look at it. While messing with it, it came back on, and since the ground wire was a bit loose where it connects to the bulb bracket, I made sure the clip was more firmly attached and reinstalled it.

By the time I got to work Monday morning, it was out again. After a second inspection last night, I found all the wires were good and the bulb filament was not broken. (Still not lit at this point).

At this point, I decided it was time to look deeper into it.

While wiggling the wires, I finally found that the lamp would light when I touched the wire directly from the bulb. Upon closer inspection, I noticed that the wire that is soldered to the exposed end of the filament wire was loose and intermittently making connection when I moved the wire correctly. Each time it would emit a small spark. I also noticed that if I held it in position so the lamp would stay lit, there was a small wisp of smoke from that broken connection.

It got me to thinking, and wondering if the temperature of the bulb is enough to melt solder.

I was able to find a reference to electronics type solder having a melting point of between 180*-190*C (360*-370*F).

While I can't find a reference to the temperature of a mini-style bulb (the H3 in this case), I did find reference that the filament reaches temperatures in the thousands of degrees.

What if the temperature of the bulb is actually melting the solder in the connections on the base to the point the wire is breaking free?

After looking at the collection of burned bulbs (don't ask me why I've kept them) there are a number of them that this same connection appears to be in poor shape.

If the wire is making a poor connection and occasionally breaking contact, I'm sure it would greatly reduce the life of the bulb.

I also think I read that someone was extending the life of their bulbs by leaving the cover off the back of the housing. This would give some support to this idea.

Any thoughts? Is anyone able to verify the bulb temps to possibly prove or dissprove this idea?

Thanks,
Ken

You'd need an infrared thermometer to got temp. But I seriously doubt cheap Automaker sloder is that low a melting point,k or that a bulb ever gets near 370 degrees.

" While messing with it, it came back on, and since the ground wire was a bit loose where it connects to the bulb bracket, I made sure the clip was more firmly attached and reinstalled it."

I mention this in the fog lamp writeup. Ground wire is an often culprit. And if it is loose but still making some contact, the resistance itself can blow the bulb. Also if you are under warranty and have frequent blowouts. GM does have a TSB out for the foglight harness. (But of course No Recall) and will replace with a heavier gauge harness when Dealer acknowledges it'* a problem and knows of the TSB.

I just had the harnesses replaced under the last of my warranty. I did get the upgraded wiring harness when mentioning the TSBs. The new setup is brighter and a different shade (more bluish or whitish). So far so good - approximately 3 weeks, which is longer than they have ever lasted in the past.

I found the same ground wire loose on both of my fogs...... But i clipped them off and now have 6000K HID H3 Bulbs...

i never had any problems with my stock lighting, i was running halogen bulbs in my GXP for almost 3 weeks before i installed my HIDs.. and on the dealer ship paper it didnt show that they replaced any fog light bulbs.. but from looking around i can see that whoever switched to HID lighting they dont have any problems, this kinda tells me that the issue isnt in the car, its in the bulbs.. so you could be right and it is melting the solder down.. ive been running HIDs in my fogs for over a year now.. and they work great..
wait... i cracked the bulb a while ago and it still light up... SOMETIMES!

I too run HID bulbs on my fogs. Can't say I'd ever go back. The oem bulbs were burned when I got the car, and the replacements burned within 2 months. HID'* have been fine, naturally.

Probably fair ..!! HID were more trusted than any other..!!

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Yeah, I just put in HID headlights. HID fogs are next. Karma bit me. Soon after the post - the fogs burned out!

dont play with Karma, just install HIDs

WHy is HID'* getting so cheaper? Now they have replacement (2) HID bulbs for $13 or $15 shipped!!! Im getting H3 and 9006 bulbs to use after i use up the limited lifetime warranty on mine...