Its only the stop/tail lights and DRLs that are dual filament.
back up light????
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back up light????
one of my back up lights was out so i went to replace it. the side that worked had 2 filaments. both light when i press the unlock on the fob. the other side, that wasnt working, was a single filament. went to auto zone, got the light they said to use. was a double filament. now the side that wasnt working works but only one filament lights up. it is much dimmer then the one that has always worked. any ideas?
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Here's whats in the manual for a '99
Replacement Bulbs
High-Beam Headlamp . . . . . . . . . . . . . . . . . . . . 9005
Low-Beam Headlamp . . . . . . . . . . . . . . . . . . . . 9006
Front Parking/Turn Signal . . . . . . . . . . . . . 3157 NAK
Back-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2057
Front Sidemarker . . . . . . . . . . . . . . . . . . . . . . . . . 194
Rear Sidemarker . . . . . . . . . . . . . . . . . . . . . . . . . 194
Rear Stop/Tail and Turn Signal . . . . . . . . . . . . . 3057
For any bulb replacements or procedures not listed here,
please consult your dealer.
Last edited by dgrant3830; Sep 26, 2008 at 06:53 PM.
Tech Contributor
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Please enter your profile and especially the year/model of your car. This has got me bugged now!
I'm wondering now if there are two different backup light modes.. daytime and nighttime therefore using the two different filaments?
I'm wondering now if there are two different backup light modes.. daytime and nighttime therefore using the two different filaments?
Last edited by dgrant3830; Sep 26, 2008 at 07:19 PM.
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im with you. the bulb has two contacts on the bottom of the bulb. the socket that receives the bulb only contacts one. im confused. on my drivers side with one contact, both filaments light up. on the other with one contact, only one filament lights up. the double filament makes sense to me. one when you put it in reverse, and the other when you put it in reverse with the lights on. however the socket only has one contact, and one lights both, and the other lights one. ive got a 2000 coupe
Last edited by ClockworkC5; Sep 26, 2008 at 07:21 PM.
Tech Contributor
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Do you have your owner's manual and if so, what does it say for the lamp?
One contact in the socket means it should normally be looking for a single contact bulb. The fact that a dual filament bulb is working is only because the the single contact socket is shorting across both lamp contacts
I looked up your car and its supposedly a 2057...doesn't make sense. Do yourself a favor and send a PM to Bill Curlee. He's the electrical expert here
I'm wondering if someone before you replaced the sockets for some reason?
One contact in the socket means it should normally be looking for a single contact bulb. The fact that a dual filament bulb is working is only because the the single contact socket is shorting across both lamp contacts
I looked up your car and its supposedly a 2057...doesn't make sense. Do yourself a favor and send a PM to Bill Curlee. He's the electrical expert here
I'm wondering if someone before you replaced the sockets for some reason?
Last edited by dgrant3830; Sep 26, 2008 at 07:32 PM.
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I'm not quite sure why you would need two filaments. The back up lamps come on and off independently of the tail lamps, so it wouldn't matter if the lights were on. The backup lamps are in the lenses by the license plate, have yours been moved to the tail lamp sockets perhaps?
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both sockets are the same and look original. im guessing that one light was replaced. there were 2 different lights bulbs when i took them out. the one that worked had 2 filaments and the one that didnt had one.
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Back Up Light
Good Luck
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St. Jude Donor '13
Maybe one side lights with the approach lights when you hit the fob. The other could just be wired to the reverse switch. Somebody should be able to tell with a wiring diagram/schematic.
Pro
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From: Bucks County Pa
Back up lamps
Good Luck
Tech Contributor
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From: Van Buren Arkansas
Wounded Warrior Escort '11
That's the only thing that makes sense is that they are using a single socket contact to hit both bulb contacts. Sure don't understand why they didn't use a single contact bulb with the right wattage though...
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It's been a while since I looked but it used to be that dual filament bulbs had staggered pins so they would only install one way. That was needed since the brake light function / turn signal filament was brighter that the tail light filament. 
On single filament bulbs the pins were set even and it could be installed two ways: IE 180 degrees off.
Does the backup light socket have a single contact but the grooves are cut for staggered pins on the bulb?
On single filament bulbs the pins were set even and it could be installed two ways: IE 180 degrees off.
Does the backup light socket have a single contact but the grooves are cut for staggered pins on the bulb?
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Well, is the contact in the socket small about the size of one of the pins on the bulb or is it large enough to touch both pins at the same time? Or, is the contact in the socket off centre so that it's only going to hit one contact on the bulb.
The contact position and the slots for the pins not being even as posted above both existing are the 2 things that would point to GM picking the dual filament bulb for that application.
I'm thinking the dual filament bulb has a brighter brake/stop filament than most common single filament bulbs so it was a better choice. Maybe it's not supposed to light both filaments but the contact in your one socket got moved. Or, it is supposed to light both and the bad one is dirty or off somehow. It's also possible the pins on the bulb aren't even enough for the socket contact to touch both at the same time.
So, describe the socket or take some good pics.
Peter
The contact position and the slots for the pins not being even as posted above both existing are the 2 things that would point to GM picking the dual filament bulb for that application.
I'm thinking the dual filament bulb has a brighter brake/stop filament than most common single filament bulbs so it was a better choice. Maybe it's not supposed to light both filaments but the contact in your one socket got moved. Or, it is supposed to light both and the bad one is dirty or off somehow. It's also possible the pins on the bulb aren't even enough for the socket contact to touch both at the same time.
So, describe the socket or take some good pics.
Peter
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took some pix but dont know how to put them up. the insert picture button asks for a url?
each socket looks identical, the contact is off center.
each socket looks identical, the contact is off center.
Last edited by ClockworkC5; Sep 29, 2008 at 12:35 PM.
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St. Jude Donor '06-'08-'10
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About the easiest site to use is tinypic.com. Once you upload the pic you get the links you can copy to post it here. Use the IMG Code for Forums & Message Boards.
If the contact is off center then it should only be hitting one of the contacts in the bulb and only lighting one filament.
Peter
If the contact is off center then it should only be hitting one of the contacts in the bulb and only lighting one filament.
Peter
