Fogs as running lights and LED CHMSL

[The Whispering Gallery]

Hi all, first let me say that I'm a big fan of CPF and have learned a lot about automotive lighting by lurking around recently. I currently have a few questions and I'm sure that this forum will set me straight to the safest and most legal way.

I was thinking about adding OEM-style fog lights to my car (08 Mazda 3) that came without this equipment. I'm already familiar with the usefulness of fog lights (going slow in very bad weather conditions) from reading Daniel Stern's website, and these situations are my main motivation. However, I could either wire the fogs just like Mazda did (can only switch on if the low beams are on) or have independent control. The reason I ask this is because I'm wondering what are the best lights for being visible when it is not necessary to illuminate the road. Currently, I just use the low beams in these conditions, but though that this could be an added use of the fog lights. I also see people using parking lights (which in my case are the same bulbs as the turn signals).

So, out of low beams, parking lights, fog lights, and proper DRLs, what are the best "running lights" for conditions when I want to be more visible, but don't need to illuminate the road?

I'm also wondering what is the consensus on aftermarket LED CHMSLs which replace the entire OEM incandescent assembly. From my perspective, I can see benefits to "instant on" LEDs, but aftermarket parts are also not usually as good as OEM and sometimes have questionable legality.

Thanks!

 

[Alaric Darconville]

Hi all, first let me say that I'm a big fan of CPF and have learned a lot about automotive lighting by lurking around recently.

Welcome to the CandlePowerForums!

I was thinking about adding OEM-style fog lights to my car (08 Mazda 3) that came without this equipment.

Unless they are the genuine OEM (not just made-in-an-anonymous-factory-and-claiming-to-be-OEM-style) they're going to be junk. And if they're OEM, they're still not magical. Save your money!

I'm already familiar with the usefulness of fog lights (going slow in very bad weather conditions) from reading Daniel Stern's website, and these situations are my main motivation. However, I could either wire the fogs just like Mazda did (can only switch on if the low beams are on) or have independent control.

There are exceedingly few situations where fog lamps alone are better than fog lamps with low beams. For the most part, this article's charts show plainly that fog lamps only isn't very useful.

The reason I ask this is because I'm wondering what are the best lights for being visible when it is not necessary to illuminate the road. Currently, I just use the low beams in these conditions, but though that this could be an added use of the fog lights. I also see people using parking lights (which in my case are the same bulbs as the turn signals).

Functionally-specific DRLs, turn signal DRLS, or the factory implementation (if the car has it) of the high- or low-beam DRL.

In Canada, fog lamps are permitted to be used as DRLs, but not in the U.S. The U.S. also requires DRLs to be white unless they are implented with the turn signals.

Driving with just the parking lamps on is prohibited in most (all?) states.

I'm also wondering what is the consensus on aftermarket LED CHMSLs which replace the entire OEM incandescent assembly. From my perspective, I can see benefits to "instant on" LEDs, but aftermarket parts are also not usually as good as OEM and sometimes have questionable legality.

There are decent (objectively good) aftermarket LED CHMSLs; such as the models described on this page. Other brands (like PIAA, for example) might not be so trustworthy.

Your Mazda 3 has yellow rear turn signals-- your likelihood of a rear-ending when turning (and signaling) is already reduced by virtue of that, but I suppose that tiny extra bit of warning from the LED CHMSL's shorter rise time could be handy, especially if you were simply *stopping*, not *turning*.

 

[-Virgil-]

Alaric is right. Fog lamps are almost entirely useless as such. Don't use fogs as conspicuity/daytime running lamps, either (they won't be legal as such in Canada for very much longer, either).

 

[The Whispering Gallery]

Thanks Alaric and Virgil for the detailed responses. It seems like it is probably best to just not change anything. There are a few aftermarket LED CHMSLs available for my car that completely replace the OEM incandescent assembly located on the trunk, but I kind of doubt that they are objectively good.

Correct me if I'm wrong, but Daniel Stern's DRL-1 module simply uses the turn signals as the DRLs, which would be identical to turning on my car's "parking lights" which are the same bulbs as the turn signals (or are they not called parking lights because of this?). I'd rather just "turn on the turn signals" when conspicuity is needed, assuming this is legal, than install a DRL module.

I guess my motivation for using something other than the low beams for conspicuity is to use less power and prolong the life of the halogen low beam bulbs.

 

[Alaric Darconville]

([Fog lamps] won't be legal as [DRLs] in Canada for very much longer, either).

Good!

TWG,

When you consider that front turn signals are designed to be seen at all times, day and night, to communicate a message effectively and without glaring, it only seems natural that they would also make excellent DRLs. Do note, if you haven't read the linked articles, that the turn signal DRL uses the major filament (higher brightness function) of the bulb, so they are as visible as turn signals are (and yes, they're on steady, not flashing).

 

[fastgun]

For a little more clarification what US federal law actually states is:
S6.1.1.4 Daytime running lamps. Any pair of lamps on the front of a passenger car, multi- purpose passenger vehicle, truck, or bus, whether or not required by this standard, other than parking lamps or fog lamps, may be wired to be automatically activated, as determined by the manufacturer of the vehicle, in a steady burning state as daytime running lamps (DRLs) in accordance with S7.10.5.

Fog lights wired to operate as DRL is what is illegal. Manually turning on your fog lights during the day may or may not be OK depending on your states law (if you are in the USA). In 2003 the NHTSA determined that fog lights are not regulated by FMVSS 108. In 2004 they amended this determination stating the federal regulation of fog light location. In my state if the visibility is below 500 feet, you must have your headlights on.

Proper DRL's or since I already have them, regular ole low beams would be my choice for conditions when I want to be more visible, but don't need to illuminate the road

 

[Alaric Darconville]

Manually turning on your fog lights during the day may or may not be [LEGAL] depending on your states law (if you are in the USA).

It may or may not be *legal* to use fog lamps during the day, depending on your State's law, but it's never *OK*. They serve absolutely no function except under a limited set of conditions, including very limited speeds. Leave 'em turned off if you got 'em, and don't install 'em unless you just really really GOTTA have them-- and then leave 'em turned off!

 

[-Virgil-]

Correct me if I'm wrong, but Daniel Stern's DRL-1 module simply uses the turn signals as the DRLs, which would be identical to turning on my car's "parking lights"

No, that's not correct. Even if the parking and turn signal functions are done by the same bulb, they are not the same intensity. The parking lamps are very significantly dimmer than the turn signals. See for yourself; turn on the car's parking lights and activate one turn signal, then go to the front of the car and compare. The DRL-1 operates the (bright) turn signals in steady-burning mode to provide the DRL function. There are also some videos on this page that illustrate the DRL (steady-burning) operation of the bright amber turn signals.

 

[Qship1996]

what is the rated lifespan of the typical turn signal bulb?

 

[Alaric Darconville]

what is the rated lifespan of the typical turn signal bulb?

For the 1157, the design life is about 1200hrs on the major filament. Your mileage may vary.

Flashing the bulb from a cold state may be more "wearing" than keeping it turned on and then occulting for the turn signal duration, since there's less cold filament shock.

 

[Alaric Darconville]

Thanks Alaric and Virgil for the detailed responses. It seems like it is probably best to just not change anything. There are a few aftermarket LED CHMSLs available for my car that completely replace the OEM incandescent assembly located on the trunk, but I kind of doubt that they are objectively good.

You're welcome! The Hella modules I linked previously *are* objectively good.

Correct me if I'm wrong, but Daniel Stern's DRL-1 module simply uses the turn signals as the DRLs, which would be identical to turning on my car's "parking lights" which are the same bulbs as the turn signals (or are they not called parking lights because of this?).

You're wrong.

The DRL-1 module

...uses the major filament (higher brightness function) of the bulb, so they are as visible as turn signals are (and yes, they're on steady, not flashing).

I'd rather just "turn on the turn signals" when conspicuity is needed, assuming this is legal, than install a DRL module.

Driving around with your hazard lights? Don't do that.

I guess my motivation for using something other than the low beams for conspicuity is to use less power and prolong the life of the halogen low beam bulbs.

The DRL-1 is probably the best way to do that. You could add on functionally specific DRLs, but then you have to find the right place on the car to put them, and make sure they're positioned well and everything.

 

[The Whispering Gallery]

The Hella modules I linked previously *are* objectively good.

I don't doubt that, but I wouldn't add that type of module (on the rear windshield) when my car has the 3rd brake light incorporated into the trunk. OEM look is preferred and outweighs the seemingly small benefit of LEDs over incandescents.

Driving around with your hazard lights? Don't do that.

Well I meant with parking lights, not driving around with flashing hazard lights. Now I know the proper terminology for the various lights, and that there are two filaments in the bulbs, brighter for turn signals and less bright for the parking lights. And this is why only the turn signal filament is suitable for DRLs, thus necessitating a DRL module vs. just turning the parking lights on.

The DRL-1 is probably the best way to do that. You could add on functionally specific DRLs, but then you have to find the right place on the car to put them, and make sure they're positioned well and everything.

Agreed. However, I'm going to stick with using the low beams for conspicuity like I've been doing. It seems that the advantages of the DRL-1 module or functionally specific DRLs (low power and save your headlight bulbs) are outweighed by the disadvantages (cost, time spent on installation, lack of manual control).

Thanks again to all for the responses.

 

[-Virgil-]

what is the rated lifespan of the typical turn signal bulb?

There are too many different turn signal bulbs for any one type to be called "typical". The car in this thread (2008 Mazda3) takes an 1157NA. The standard variant of this bulb is 1200 hours or so (depending on manufacturer) at 14.0v, which means a little over 2100 hours at a realistic operating voltage of 13.4v. There are long-life versions of the 1157NA with a 2400-hour major filament rating at 14.0v (over 4200 hours at 13.4v).

 

[-Virgil-]

lack of manual control

You can install an override switch as part of your DRL-1 installation, if you want to (or do it the slick way and wire it up to the parking brake warning light switch so the DRLs turn off when you apply the parking brake, like on a factory installation)

 

[The Whispering Gallery]

You can install an override switch as part of your DRL-1 installation, if you want to (or do it the slick way and wire it up to the parking brake warning light switch so the DRLs turn off when you apply the parking brake, like on a factory installation)

Interesting...I will have to look into that.

 

[Unicorn]

By "manual control" do you mean that you want to be on total control of when they come on or not? There may be an advantage to having them constantly on during the day time (or whenever your headlights are off) and that would be an insurance discount if your insurance company offers one for DRLs. Usually if they do, it's required that the DRL be automatic.

 

[The Whispering Gallery]

By "manual control" do you mean that you want to be on total control of when they come on or not? There may be an advantage to having them constantly on during the day time (or whenever your headlights are off) and that would be an insurance discount if your insurance company offers one for DRLs. Usually if they do, it's required that the DRL be automatic.

I'd like them to come on automatically when the car is on, but also wire a switch so they can be turned off just in case I don't want them on for some reason. Unfortunately, no discount with my insurer. I like the Philips modules best so far...perhaps next month I'll pull the trigger and then post some pics of the installation.

 

[The Whispering Gallery]

Wanted to post the information that I've been gathering. The best case scenario is to add LED DRLs at the location of the fog light hole covers. This would give useful, attractive DRL functionality (as opposed to not very useful fog lights) to the sort of cheap-looking plastic cover pieces. Here is the front of my car with one of the covers removed.

Philips seems to offer the best combination of price and quality, but the problem is that my bumper is curved. The installation instructions say that the optics are designed to allow 10 degrees maximum rotation toward the outside of the car. The carpenter's square shows approximately how a straight-ahead facing DRL would be oriented.

To my knowledge, there is only one quality DRL strip whose optics are designed for mounting on such a curved surface, Hella part number 010043801: http://www.myhellalights.com/index....ning-lights/universal-daytime-running-lights/. Unfortunately, it is huge. Here is my fog hole cover with cardboard cutouts that are the size of the Hella and Philips 8 LED DRL footprints.

Secure mounting would definitely be a challenge, and if it doesn't look close to OEM, then I wouldn't be happy with it.

That's where I'm at right now. Still thinking about Daniel Stern's DRL-1 module as well.

 

[noname456]

Curious what the outcome was

 

[The Whispering Gallery]

I installed the DRL-1 module, which worked without issue. I did also install the override switch mentioned but rarely used it. I installed new Philips bulbs at the same time which didn't burn out for the five years I owned the car after installation, although I probably only drove 3-5k miles/year.