Why are reverse lights dual filament?

Bow_Tied

Original poster
Member
Dec 21, 2014
453
London, ON
I changed a reverse light bulb recently and noted that for the envoy they are 3157s which appear to be a dual filament. The socket appears to be designed to light both filaments at the same time. What is the reason for this vs. just using a single filament? The only thing I can think of is it's a bit brighter with both filaments lit. Or have I misunderstood things?
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
Use the same socket across the entire lighting bar saves costs and keeps wiring consistent.
 
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Bow_Tied

Original poster
Member
Dec 21, 2014
453
London, ON
Thanks for the guess. These are however stand alone sockets.
 

djthumper

Administrator
Nov 20, 2011
14,950
North Las Vegas
On the Envoy they are separate, but they kept them in line with the rest of the platform.
 

xavierny25

Member
Mar 16, 2014
6,323
Staten Island, N.Y
On the Ascender they went with a 921 bulb and socket.:explode:
Envoy's dont put out enough light when backing up do to the lights being at the bumper. That's why I did a quad back up light with the added Asceder tail light assembly...The wife really loves it and serves its purpose.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
They went with 921 for backups on the 9-7x too. I had to go with LEDs there to increase light output as they were pitiful.
 

Bow_Tied

Original poster
Member
Dec 21, 2014
453
London, ON
Sounds like there wasn't any consistency across the platform, separate lights on envoy and different bulbs on ascender and saab, way to go GM lol. Oh well, just curious, nbd. I put in LEDs while I was in there, made a little difference, whiter light.
 

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