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angrychicken
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Joined: November 22, 2013
Posts: 166
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 Posted: Fri Apr 22, 2016 6:52 pm Post subject: melted tail light? |
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Weird thing today. Walked out to my van, the passenger tail light was melted...
Nothing was hot around the van. Pig tail is fine.
I'm wondering if there was a short or something within the housing that caused resistance and melted the lenses?
Anyone seen/heard of this happening before? Easy fix, other than I'm half way across the country from my home. But I do have a replacement en route.
I'm just worried about this happening again and starting a potential fire. |
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DwarfVader
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Joined: July 28, 2015
Posts: 646
Location: Missoula, MT
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| Posted: Fri Apr 22, 2016 7:16 pm Post subject: Re: melted tail light? |
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your neighborhood cats are polydactyl and have learned how to use fire...
be very afraid...
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I'll find my van someday, or it will find me. |
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djkeev
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Joined: September 30, 2007
Posts: 32574
Location: Reading Pennsylvania
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greebly
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Joined: August 27, 2009
Posts: 966
Location: Here and now
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| Posted: Fri Apr 22, 2016 7:42 pm Post subject: Re: melted tail light? |
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| Many times? |
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angrychicken
Samba Member
Joined: November 22, 2013
Posts: 166
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| Posted: Fri Apr 22, 2016 8:07 pm Post subject: Re: melted tail light? |
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| I've did read some bulbs can do that. But it's weird, I don't ever remember replacing any of the bullbs in the years I've had it. |
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bluebus86
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Joined: September 02, 2010
Posts: 11075
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| Posted: Fri Apr 22, 2016 9:09 pm Post subject: Re: melted tail light? |
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metallic films on building windows, specially doible paned windows which can take on a dished shape can focus sunlight into a plastic melting beam. melting of plastic car parts by metallic window films concentrating sunlight by the bowed glass has been documented.
the offending reflecting window can be across the street.
If a brake light bulb caused this, Id expect the melting would be concentrated in the brake light housing. or what ever light bulds housing that got too hot. if the general tailight housing was melted, then an external source maybe the cause rather than a specific high watt bulb.
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djkeev
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Joined: September 30, 2007
Posts: 32574
Location: Reading Pennsylvania
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djkeev
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chase4food
Samba Member
Joined: February 27, 2016
Posts: 636
Location: PNW im Amerika
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| Posted: Sat Apr 23, 2016 7:20 am Post subject: Re: melted tail light? |
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Dave. Keep up with FUD dissemination. 
http://uberhumor.com/aftrmath-of-explosion-at-chemical-plant-in-louisiana
I would have thought it is an artwork in a modern arts museums.
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- Vince 飲食玩睡
what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei |
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chase4food
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Joined: February 27, 2016
Posts: 636
Location: PNW im Amerika
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| Posted: Sat Apr 23, 2016 7:35 am Post subject: Re: melted tail light? |
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Automotive incandescent bulbs are designed to generate a lot of heat  . Ok, not exactly the design objective, but rather a byproduct of wanting them to last in a high vibration environment and extreme temperature range. They run very hot, especially the brake light bulbs.
The plastic lenses should not melt for no reason, however, as all car makers test them under the extreme conditions.
The possible cause can be:
Corroded contacts creating the right amount of resistance and this spot cause very high power dissipation.
Someone installed incorrect bulbs - thought the old school bulbs are designed to minimize one from inserting a wrong bulb.
Note the vanagon "circuit board" that is formed by injection plastic housing with metal conductors hot melted in place. If these hot melt plastic rivets deteriorate the metal conductors can short. I think this is the most likely scenario.
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- Vince 飲食玩睡
what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei |
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chase4food
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Joined: February 27, 2016
Posts: 636
Location: PNW im Amerika
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| Posted: Sat Apr 23, 2016 7:38 am Post subject: Re: melted tail light? |
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Here is a better photo of the plastic rivets and the metal conductor in the plastic circuit board. I did not add the text in there.
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- Vince 飲食玩睡
what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei |
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bluebus86
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Joined: September 02, 2010
Posts: 11075
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| Posted: Sat Apr 23, 2016 8:53 am Post subject: Re: melted tail light? |
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| chase4food wrote: |
Automotive incandescent bulbs are designed to generate a lot of heat . Ok, not exactly the design objective, but rather a byproduct of wanting them to last in a high vibration environment and extreme temperature range. They run very hot, especially the brake light bulbs.
The plastic lenses should not melt for no reason, however, as all car makers test them under the extreme conditions.
The possible cause can be:
Corroded contacts creating the right amount of resistance and this spot cause very high power dissipation.
Someone installed incorrect bulbs - thought the old school bulbs are designed to minimize one from inserting a wrong bulb.
Note the vanagon "circuit board" that is formed by injection plastic housing with metal conductors hot melted in place. If these hot melt plastic rivets deteriorate the metal conductors can short. I think this is the most likely scenario. |
lots of incorrect info in the above quoted post.
the high heat output of these bukbs is not a byproduct of wanting them to last in a high vibration enviroment nor an in an extreme temperature range.
the high heat is determental to vibration resistance and is much higher than the ambient temperature range. the filiment gets white hot, in excess of 2500C. this results in increased electromigration, which causes thinning ot the filiment thus reducing vibration resistance, the extreme heat range is do almost entiely to the heat of the filiment. the high temp is not a by product of the extreme temperature range, it is the cause of it.
If there would be a short in the bulb holder, the short would either be flowing too much current and blow the fuse, or if the short was high reistance, would be limited in current flow, simular to the high resistance of the bulb. the heat of the short should it not blow the fuse would be simular to that of the bulb. A short that does not blow the fuse would heat the shorted metal bracket, which has a rather large surface area to disapate the heat into the bulb holder assembly. that would melt first, rather than the lense. if the holder melted, it is highly likely that the metal parts that are shorted would move as they are held by the plastic which is melted. they would either move toegther more, causing a lower resistance path, hence more current and hence a fuse blowing, or they may more further, reducing or ending the current thru the short, resulting in less heat.
as far as corroded contacts at the bulb base, wrong again in the conclusion. true you may get a hot spot at the high resistance contact, but you will also see a reduction in current thru the bulb, hence the bulb would be dimmer and cooler. think of series resistance, the resistance of the bulb, and that of the corroded connection, you still will be limited by what the circuit can provide by the fuse size, or the maximum voltage of the system, which ever is less.
The stop lights are not designed for continuous duty, a shorted stop light switch could leave the bulb on continous and that could cause the plastic lense to melt, localized around that turned on bulb. the problem can be worse with higher watt bulbs. if both left and right side stop lights did not melt, then it is unlikely the bulb was stuck on, as both sides would be affected, unless one side has a defective bulb or connection or one side has a higher watt bulb.
Anyway a corroded contact should not cause the lense to melt, nor should a short in the metal traces as the system is fuse protected from significant shorts. if only the lense is melted and not the housing, then a short in the traces would not be the problem.
once the original poster replaces the lense, consideration should be made on the the correct wattage bulb, or better still a cool running led bulb, which can be brighter and is quicker acting than conventional bulbs.
one more trick to increase brightness of the lights without resorting to high watt bulbs is to .
line the inside of the housing with silver reflective tape. I have done this on all the tail bulb housing and found a significant increase in brightness. the black plastic interior of the bulb housings is not very good at reflecting the light, the silver tape lining the inside of the housing give a marked improvement in light output. you may need to cut small strips of the tape and use a tweezer to get the tape in the housing, but once all the black surfaces are covered you will be pleased with the inccreas in light output.
the often unused red fog light location can have a bulb added also, you will have to fabricate a contact for it, I wired mine in with the running light.
but leds are really the way to go. get red for the red lights, not white as a white led will loose a significant amount of brightness when the light is passed thru the red lense. so use a red led for running and stop lights. of course use a white led for reverse light and yellow for turn light. not all led light bulbs are as bright as the stock bulbs, so select cafefully.
the led will reduce current draw, meaning the switches will last longer, you wont have the worry of melted plasric if the stop light gets stuck on, (nor a dead battery as soon) and the leds do turn on faster, important for stop lights. the turn lights will require an inline resistor if you go with leds there in order to allow the flasher can to work properly. I kept the stock bulb in the flasher sockets, but went with led in the reverse, running and stop light positions, along with silver tape housing liner. much brighter now!
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IdahoDoug
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Joined: June 12, 2010
Posts: 10248
Location: N. Idaho
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| Posted: Sat Apr 23, 2016 9:07 am Post subject: Re: melted tail light? |
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Nice summary Blubus. Agree a lot can be deducted from a photo of the lense. And agree stuck on stop lights can priduce enough heat to damage in concert with direct sun on a hot calm day. Any suggestions for a quality red LED? Also, I got an excellent blinker recommendation from Daniel Stern - a Honda halogen bulb I think. Will share later.
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chase4food
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Joined: February 27, 2016
Posts: 636
Location: PNW im Amerika
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| Posted: Sat Apr 23, 2016 9:28 am Post subject: Re: melted tail light? |
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| IdahoDoug wrote: |
| Nice summary Blubus. Agree a lot can be deducted from a photo of the lense. And agree stuck on stop lights can priduce enough heat to damage in concert with direct sun on a hot calm day. Any suggestions for a quality red LED? Also, I got an excellent blinker recommendation from Daniel Stern - a Honda halogen bulb I think. Will share later. |
Always nice to have a self-professed automotive industry insider chimes in, especially the suggestion that everyone should take up a hobby of changing all the evil bulbs to LED. Cannot argue with one that "helped designed the Luxus or what ever". For full disclosure, I "helped design" F16, aviation HUDs, cruise missiles, initial guidance system, and countless most advanced electronic systems.
Admin note: Some comments about another site member were removed. Please stop arguing and taking jabs at one another.
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- Vince 飲食玩睡
what Isolde wants Isolde doesn't always get, 4 I know what is best for her - Liebe macht frei |
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angrychicken
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Joined: November 22, 2013
Posts: 166
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| Posted: Tue Apr 26, 2016 10:07 am Post subject: Re: melted tail light? |
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Here it is when I first saw it. I'm not at home but will post mot pics of the housing/lenses when I get there.
But basically, it looks like the lenses itself melted. The housing, for the most part, seems intact. As in it it not melted. I think there is a little damage from me pulling apart everything to extract it. The wiring looks to be intact.
Thanks for all the posts/help guys! |
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Ahwahnee
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Location: Mt Lemmon, AZ
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| Posted: Tue Apr 26, 2016 11:24 am Post subject: Re: melted tail light? |
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Crikey, that's much worst than I imagined. Seems unlikely to me that a single hot bulb could do that much melt.
I think I'itoi there had something to do with it. |
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angrychicken
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Joined: November 22, 2013
Posts: 166
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| Posted: Tue Apr 26, 2016 3:23 pm Post subject: Re: melted tail light? |
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djkeev
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dhaavers
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| Posted: Tue Apr 26, 2016 4:22 pm Post subject: Re: melted tail light? |
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Someone set up and ran their torpedo heater right behind you...? Agree that it looks like an outside heat source.
Where and how long was the van parked? Can't imagine what happened here... 
- Dave
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angrychicken
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Joined: November 22, 2013
Posts: 166
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| Posted: Tue Apr 26, 2016 5:09 pm Post subject: Re: melted tail light? |
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Totally agree it's odd.
I can't figure it out. Not sure exactly when it happened. But the the only place it was parked was a driveway and a plaza parking lot where I had coffee. |
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