I have been discussing this topic in another thread and there seems to
be some confusion. Why is a dual filament bulb used on the daytime
running lights on the chevy full-size vehicles? I have verified on my
2000 Silverado that only one filament is used for the DRL's. I have
tested them with the turn signals on and the parking lights on and low
beams and high beams. None makes the second filament turn on. One
poster suggested that it was for the flash to pass operation during the
daylight (when the headlights are off). This might be but is
impossible to test by myself. I do know that when you flash to pass,
the high beams are activated for sure but maybe the second filament in
the DRL is activated too? If so, that seams like overkill.
The reason this all came up is because I was wondering if the life of
the crappy DRL bulbs could be extened by flipping the bulb over in the
socket and switching filaments. If the second filament is never or
rairly used, I thought it would be a neat trick to extend bulb life.
Or at least a temporary fix so that you don't drive around with a truck
that looks like it has a black eye.
I have also read that there is a heavy duty replacement that should
last longer. What are the numbers of that bulb? Anybody with
experience with the LED replacements? For the price they better really