Bad bulbs. I don't know the 4-digit number of the DRL bulb in the current
GM trucks, but it begins with a 3. The heavier replacement bulb begins with
a 4 and has the same last three digits. Someone once told me that it has to
do with the fact that the original bulbs when specified by GM were rated for
12v, but the truck's electrical system actually runs at 14+v, about a 20%
increase over spec in voltage which was the cause for the shortened life
span of the bulb.
Cheers - Jonathan
Thanks for the information Jonathan. It seems like every 00'+ Chevy truck I
see on the road has one of the DRL's burned out and I have always wondered
about this as well. Curiosity is finally answered..............
Well, Jonathan, I don't have a clue as to whether you're right or not. I
bought my 99 and wanted to change my DRL's to amber. So, I pulled the stock
3157's and put in 4157na/LL. I've run them for 22 months and haven't had
one burn out yet. I have changed one 3157 turn signal, and one 194
park/turn signal in the same period. Unfortunately, I also had one of my
low beam silverstars go south on me. Dang it - they're expensive! I've got
a bunch of extra lights on mine. Some are LED's and some are clearance
type lights. The worst light on my truck is the high mount 3rd brake light.
It works ok, but it is so chincy(?) it looks like they went into the back
alleys in Taiwan to find the cheapest POS that has ever been invented. Its
the all-time worst design and I hope the guy lost his job over that one.
a 4157 is a heavy duty bulb. N/A is the code for Amber. LL is the code
for Long Life.
I have replaced 3157 N/A's (3157kNA) with 3457 N/A's (3457NAk) before
and not had an issue. Just like replacing 161's with 194's.
Aha, you learn something everyday. That has been bugging me for a
while. I thought the flash-to-pass only turned on the high beams
briefly. Let me ask you this then; if my DRL is burned out, can I
remove the bulb and flip it over so that the burned filament is for the
flass to pass and the good one is the DRL?
It will flip the filaments; then the drl won't work. I missed the thread
where someone said it was for flash to pass. I have a 99 silverado - my
flash to pass turns off the drl and flashes the high beam. If you have
something like a cavalier or a saturn, it uses a reduced voltage to the high
beam. So if you flash to pass, it applies full voltage which makes it the
actual high beam.
I think George is agreeing with you, Williams. He is just saying that
you can indeed flip the bulb over and switch the filaments. Which I
personally think is a pretty neat trick since those bulbs burn out
about every 6-9 months. At least their life can be extended sort of.
I saw in a different thread that there was a heavy duty version of the
same bulb that should last longer. There are also LED replacements
that probably last about forever but they would have to to justify the
price. They are like $16 if my memory serves.
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