Help me pick turn signal bulbs

[Quattro Pete]

So I noticed that the two front turn signals light up different color - one is whiteish, the other - yellowish. Probably the previous owner replaced one of the bulbs and didn't get a matching one.

Anyway, the car is an '02 530i with HIDs; sylvania.com suggests a 7507A bulb for both front and rear turn signals. But I see some websites sell 1156A bulbs instead. Can I use 1156 in place of 7507?

http://www.sylvaniaautocatalog.com/new_s...,18,20,24,25,26

The 1156 seems to have a much longer life but it's also designed for slightly higher voltage (12.8 vs 12). Is this OK?

I don't need any fancy bulbs. Just regular replacements that I can pick up at AutoZone, probably the white version for the front blinkers and amber version for the rear.

Thanks.

 

[JustinH]

The amber version is for the front corners, it lights up amber.

The rear tail lights take white, because they are surrounded by the red tail light. (unless you have weird clear tails or something)

 

[Quattro Pete]

Actually my rear blinker lights are white, so they would need an amber bulb.


But I think I figured out the difference betw. 7507 and 1156 - the little nipples on the base are in different locations.

 

[Quattro Pete]

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The amber version is for the front corners, it lights up amber.

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Also, is it against the law for the front blinkers to light up white? It's allowed in Europe, and if I remember correctly, just a few years back it was not allowed in the US, but maybe something has changed recently?

 

[Jim 5]

a fair number of BMW guys will spring for the chrome plated amber turn signal bulbs. If you have clear turn-signal housings, then the chrome plated ones will get rid of the "egg yolk" look of the amber bulbs (not lit) in the clear housings.

I'm sure they put out less light though.

You can look at them on many bmw aftermarket sites including http://www.bimmian.com/product.htm?veh=46&item=SOL

 

[Quattro Pete]

Thanks. Unfortunately my housings have the yellow inserts anyway. I just pulled the bulbs: turns out the fronts are 3457A and rears 1156A. So much for trusting sylvania.com.

 

[RacerE7773]

I find it confusing when the owners manual/look up book at the store says one number; you buy that set of bulbs, then pull the original bulbs and they are a totally different number.

 

[Quattro Pete]

Even stranger is the fact that the 3457A is a dual filament bulb, but this bulb is only used for turn signal indication, so what's the second filament for?

It's also possible that it's not the original bulb (previous owner may have installed an incorrect one). It's made by Sylvania. I thought Sylvania name was only used in North America. If it was an OEM bulb installed at the factory, it would have been something European, like OSRAM. Of course nowadays the two companies are the same, but I thought back in 2002 they were separate.

 

[JustinH]

Perhaps it uses half of the filament when the running lights are on, and the other half for the blinker.

 

[Quattro Pete]

Here's the deal...

Parking lights on:

Driving lights (low beams) on:

The turn signal light (not lit in both photos) is the one directly to the right of the low beam. Is it possible that one of the filaments of the turn signal light is what's lighting up that amber corner position light? They appear to be in two separate enclosures, so I don't really see how it's possible, but then I don't see a dedicated bulb listed for that amber corner in any literature either, so maybe that's it?

 

[DracoFelis]

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The turn signal light (not lit in both photos) is the one directly to the right of the low beam. Is it possible that one of the filaments of the turn signal light is what's lighting up that amber corner position light?

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Maybe. However, you would have to look closer (than we can see from these photos) to know for sure. And you might have to unscrew/remove the lens assembly, to get a good enough look, to tell for sure.

Is it possible for you to see the wiring leading up to this bulb's socket? If so, do you have 2 wires leading to the socket, or 3?

If (as I'm guessing) it turns out you actually have 3 wires leading to the bulb (or 2 wires + the car ground, which is the moral equivalent of 3 wires) than it is almost certain that the car was designed to make use of a 2-filament bulb. In that case, my guess would be that one filament (probably the brighter one) was designed for normal "turn signal" use, and the other (likely dimmer) filament was designed as a "running light" (for example, to come on at the same time as your headlights). If they designed things this way, the car maker was effectively making one (2-filament) bulb serve the purpose that would normally be done by 2 separate bulbs.

Of course, if there is only 2 wires (or 1 wire + the car ground) leading up to that bulb socket, than the car maker intended for that to be a 1-filament turn signal bulb. In that case, some (previous) car owner, just put the wrong bulb in the socket (i.e. found a bulb that was "close enough" that it would physically fit, even if it wasn't the "right" bulb).

 

[Quattro Pete]

Thanks. Yeah, I should have mentioned that before - there are only two wires leading up to the socket.

 

[DracoFelis]

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there are only two wires leading up to the socket.

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Then the big question is: Is there also an electrical connection between the car's body and that socket?

Remember, many car makers have used a car's entire metal body, as if it was one big (common) electrical wire (thereby allowing the car maker to eliminate one wire from many different spots on the car). So if there is an electrical connection between that socket and the car's frame (possibly via a "mounting screw" that is performing double-duty), than you have the equivalent of 3 wires. And 3 wires (or the equivalent, by having two wires plus an electrical connection to the car's body itself) is what you would expect for a car light socket designed for 2-filament bulbs.