Doing some work on rear lighting and curious why the back up bulbs have 2 filaments? I thought they were either on or off. Or do they just both come on for a brighter light ...which makes me wonder why they just didn't use a larger single filament.

Please forgive any stupidity here, it is not intended :-).

Jay

Think I would more suspect someone put the wrong bulbs in there..... Check the socket, see how many contacts there are at the bottom. (should only be one.) It's entirely possible that this was someones Idea of how to get more light while backing up, for minimal cost. (and it likely worked. )

Its interesting though that when I look on Autozone, it shows the same dual filament... It's not that big a deal, just confusing a little. Thanks HeyYou

We can drop this. I'm seeing a variety of bulbs, but, based on your feedback, I'll go with the single filament bulb. Wonder if that will have any effect on the turn signal issue. Thank you.

Huh. That is interesting. I'll have to look at mine. (of course, my backup lights currently don't work..... and it isn't the bulbs.....

Owners manual says it's a 3157 witch is a duel filament bulb. Have to look at the wiring and see if both are used.

The manual is wrong there, it's the ubiquitous 1156 bulb. 3157 is a flat socket dual filament bulb for tail/brake lights.

The back up light socket is flat as well. When I search for an 1156 bulb, it shows me a round (old style) bulb --- so that wont fit. Is there an 1156 Flat bulb?

I'll admit I'm somewhat stumped on this one. Rockauto and Napa only show 1156 for the backup, OReilly's also lists 3157 which is a dual filament flat style. I have no idea why the backup would use a dual filament but I'd guess only one of them is used.

Interesting. Thank you all for your feedback.