Rear Fog Lamp: Red 921 LED replacement?

I caught up on my "Rear Fog" reading and was disheartened when Cheam relayed the $450 price tag for the drop-in replacement fixture, from Subaru Germany (replaces the left reverse lamp).

 

So what I'm thinking is, rather than spring for the new overpriced fixture, what is the chance of success retrofitting the existing reverse light with a colored LED replacement lamp?

 

SuperBrightLEDs.com sells a red drop in 921 (reverse lamp bulb type) LED replacement. It's a 9-LED element with a 34mA current draw, built-in resistor, and a claimed 6280 mcd light output with a 26° beam.

 

The beam pattern is a little wide, but not too awful. However, the clear reverse lamp lens may diffuse the light pattern even more. This would be a complete waste of time if the converted light is no brighter than the the tail lights.

 

One problem I'm having is judging the equivalent light output of 6280 mcd (milli-candellas). I wonder how easy it is to to modify the reverse lamp assembly to fit two or three of these LED replacement bulbs.

 

Just for reference, here's a photo of a Legacy wagon owned by "redline 76" with an "official" rear fog conversion (albeit the Japanese RH side), from an earlier post on the topic (link):

 

http://www.booboodog.net/images/legacy-rear-fog.jpg

I've been thinking about wiring some in too.

Brighter than the brake lights

I was just looking over the 921 LED bulb specs again, and noticed that they list light output as 6280 mcd (millicandela) PER LED. That would provide me 56,000 mcd -- if it's correct to sum the collective output.

 

Now, it's difficult to draw a comparison between between LED vs. incandescent lighting, with a whole list of explanations given by the various web searches I've done.

 

However, I did find an article which described a 100w filament bulb as outputting an equivalent of 135,000 mcd (as viewed straight on by an observer, not total light output).

 

By deduction, since the traditional rear fog lamp replacement bulbs I've located (those that aren't LEDs) are anywhere from 18w to 30w, perhaps a single one of these 9-LED clusters will do the trick.

 

At less than $2 apiece, I've ordered up a few and will experiment in the coming days to see if a rear LED fog lamp is as obtainable as a few bucks out-of-pocket and a quick re-wire of the reverse lights.

 

For giggles, I ordered a white unit as well to compare output to the stock reverse lamp.

 

Watch this thread for proof-of-concept photos, hopefully late this weekend.

 

(illustration and output chart borrowed from SuperBrightLEDs.com)

 

http://www.booboodog.net/images/921-led-bulb-1.jpg

 

 

http://www.booboodog.net/images/921-led-bulb-2.jpg

To resurrect this thread....

 

Note that I am *not* seeking a 921 replacement, but rather, I am seeking DIY solution for my sedan.

 

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I like to begin by saying that I'm asking for your collective input on this. Good and bad. I haven't started this project, yet, and I want to see if I can bounce some ideas off my fellow brothers and sisters here, as well as get some advice. Therefore, nothing can't be undone, so to say.

 

I've recently obtained some interior (puddle and roof dome, sedan) LED arrays from V-LEDS, and am pleased with their "performance" and cost.

 

My original intent had been to simply graft a Piaa Deno3 onto my rear deck. Yes, I know, it'll make my rear-end look rather crowded, but that's no big deal in my eyes - I've already got those huge canisters back there, anyway, and also have a host of jammer heads (either there already, or will be added soon). An extra piece wasn't going to make me frown much.

 

Besides, I think from this past post, it should work very well in its intended application:

 

http://www.legacygt.com/forums/showthread.php?t=23113&highlight=piaa+deno

 

 

However, after getting my interior setup from V-LEDS, I got another idea.

 

What if I were to utilize the sedan's central reverse-light reflector housing as my rear fog?

 

What if I used one (or even two) of these types of bulbs:

 

http://frickinbrite.com/catalog/prod...roducts_id=314

 

-or-

 

http://frickinbrite.com/catalog/prod...roducts_id=331

 

[ Note that I'm not asking of the specific bulb fitment/number, but rather, what you think of using either type of LEDs - i.e. the high-power 3W refractor versus the "High-Power SMT" configurations. ]

 

And utilized the sedan's left rear back-up light "area" to double-duty as my rear fog?

 

I'd imagine that I'd get plenty of "fill" of the reflector housing from the way these LEDs fire - but I'm concerned with whether or not I'd get enough visibility from far enough away, "straight-on."

 

At the same time, I would also doubt that the PIAA Deno3's set of LEDs would too greatly exceed the output of these units from this particular vendor - and furthermore, I'm also debating whether or not the "fill" of the reflector housing from this new generation (for automotive purposes) of LEDs, which has specific parts of its array that are dedicated just to "fill" the off-angles which previous-generation LED-bulbs have had trouble with (i.e. the items cited above, in this old post which I've resurrected), may not offer some additional benefits for off-angle viewing, versus the PIAA Deno3?

 

Your thoughts?

Addition:

 

While going through the SuperBrightLEDs website, I also found this item:

 

http://www.superbrightleds.com/specs/1156-xLX5.htm

 

For my application, I'd graft-on a 1156-style, "constant-on" socket (to switch between simple on/off, for when I need/don't need the rear fog).

 

The red 1156-RLX5 seems to carry a lot of power, at 132 lumens.

 

Perhaps I can use one of the multiple-facet arrays to enhance overall reflection from the back-up light's reflector housing and "fill" the area, and use one of these "5W" (a 3W LS side-firing, plus an array of 4 surface-mounts) pieces to achieve the end-on intensity that I desire?

OK, everyone....looking for some ideas/help/suggestions.

 

Thanks to brother peterjmc, I've just obtained a spare left (driver's side) tail-light unit.

 

This means that I'm going to, soon, go ahead with my planned LED-based rear-fog project.

 

I've never physically cut/chopped into the chrome/"reflectorized" plastic before. Is there anyone who has, here, and can offer me some words of wisdom? Will the finish "chip away" uncontrollably if I used a Dremel-type rotary cutter to make the holes necessary?

 

Any and all thoughts are welcome.

 

I never saw the above posts, so I'll chime in now.

 

First of all, I would think that you would want just the straight facing arrays for a "fog" application. Since you want the most light reaching the most distance, I would think this would be most effective? Also, are you planning to replace the reverse bulb completely or have an additional bulb in the area? I would be very interested as to the heat dissipation if you were to have two bulbs in there.

 

On a side-note, how did your interior lights work out? I would be interested in a lower-cost alternative to some of the LED interior lighting currently available. Is the product you have Legacy-specific, or is it generic that is the same size as the incandescent bulbs?

 

Thanks for the input on this, and good luck on your rear-fog venture:)

^ Thanks, bruddah.

 

I'll address your questions/comments in "reverse" order. No pun - well, maybe slightly so - intended.

 

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The interior lights are working out great. The overhead dome arrary (24 "surface-mount" LEDs) is slightly brighter than I'd anticipated, but the trade-off there is that I actually get to see what Anna's dropped into the recesses of each footwell. I don't know if she'll sleep through their activation, yet, though, since I haven't taken her on any night-time trips.....

 

The door/puddle 6-"SMT" arrays were a difficult fit into the factory pockets, and although I got it to work by "tilting" the arrays, I'm not sure it's a look everyone will appreciate (although it does get more light "on floor"), and a different (i.e. "bulb-based" - where the LEDs are arranged as the factory "bulb" shape) may be an easier way to go.

 

----

 

As for the rear fog:

 

Indeed, I do want the most intense aspect of the light to be seen "face-on rearward."

 

Just last night ( by the timing of your post, I'd say it was about the same time, actually! go figure! ), I'd thought about using a flat "array," as with the interior replacement solutions, as the primary "rearward" setup, too. However, given their output, (yes, they're bright, but bright enough?) I honestly don't know if this is viable. My current plan is to "mock" one of these installs, using the hardware currently at my disposal (i.e. to use one of my current 6-SMT arrays), to see what I think about light output.

 

Indeed, I do plan to run a multiple-bulb solution. The plan is to utilize the current "reverse light" hole, which is centralized, for the main "face-on rearward" element, while relocating the reverse light to a side location (thus drilling a new hole), as well as incorporating a more radially-firing LED "array" bulb to the other side (thus requiring a final, second, drilled hole), to help "fill" that reflector area when the reverse-fog is in-use, to further maximize visibility.

 

Originally, as you can see in post #7, I'd planned to purchase a "5W" 1156-based solution as the primary "face-on rearward" fog element. However, there's a fine-print line noting that this LED setup may self-regulate (temperature) and automatically dim under cases of increased temperature from prolonged runs. I do not think that this is acceptable, for the safety aspect of the rear-fog application.

 

Thus, yes, I do have a heat-dissipation concern, but it's not really in the same manner that you'd so wisely suggested above - since I do not intend to have both the reverse bulb (which, for me, is already an overwattage application) engaged at the same time as the rear fog setup.

 

Nevertheless, this "new" heat concern is what brought me nearly full-circle in terms of selecting the LED-based bulbs for this project (returning my thoughts to the various items offered by V-LEDS), and also what spurred my small brainstorm, yesterday evening, at around the time of your post ( such coincidence! maybe you're telepathic? ), to utilize a surface-mount array, which, in looking at the tail-light assembly, there could be a potential access-point that would cut down on the technical difficulty of this project, considerably.....

 

Thanks for contributing, BrownBoy - please, keep the ideas coming!

Damn, I forgot about this project- maybe I'll work on it this summer.

 

I hope to have this project completed for *next* year's winter season.

 

I hope to have this project completed for *next* year's winter season.

 

Yeah, I'll probably never do it either

 

How you been, man?

Good bro, good. Very busy with both work and home stuff (Anna!!!), but good.

 

Since Winky is pretty much "static" now, with only ancillary mods going, I've been off the mainstream here, more or less. Also, things over on the speed-detection countermeasures area have been rather busy, with some recent happenings, so that's taken a lot of my spare time and attention.

 

I think that in another two years or so, I'll have another burst of activity here again, as I'm likely go go the much-bigger-turbo route at that time.

 

Until then, I'm just "checking in."

 

It's good "seeing" you again, too, bro. Hope all's well in your hood, too.

Good bro, good. Very busy with both work and home stuff (Anna!!!), but good.

 

Since Winky is pretty much "static" now, with only ancillary mods going, I've been off the mainstream here, more or less. Also, things over on the speed-detection countermeasures area have been rather busy, with some recent happenings, so that's taken a lot of my spare time and attention.

 

I think that in another two years or so, I'll have another burst of activity here again, as I'm likely go go the much-bigger-turbo route at that time.

 

Until then, I'm just "checking in."

 

It's good "seeing" you again, too, bro. Hope all's well in your hood, too.

Good to hear man- things are cool here. WEnt off the grid for a while during my divorce, met a nice girl (she's a Doctor too, w00t!) and picked up a Formula Firebird to play around with- pretty much done with XT mods although there are a few, like the LED foglight, that still beg me to mess around with.

You know I've been wanting to do this too, hmmm

jedi - Good to see that Teh Farce (or is that The Force?) is still strong with you.

 

Hopefully, I'll be able to dream up something that's acceptable in this application, and I'll definitely keep both of you (you too, brother Aczwild, although, in your case, I would just suggest hitching your lightbar-shod '96 to the back of your SpecB, with the former in "reverse," of course - that'll insure PLENTY of lighting powa!!!!

 

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Took a look again at the 6-SMT array that I'm using as my front door puddle lights.

 

I'll be darned....it's actually pretty danged bright.....

OK, it was snowing pretty nicely when I got home today.

 

From about a distance of 50 ft., the 6-LED "SMT" array from V-LEDs, residing in my door puddle area (thus behind the much more opaque cover), is at least as bright as my running lights, if not brighter.

 

I'm going to re-think this project, based on the heat-related concerns from running the "5 Watt" LED solution, which I now don't think will be feasible, from a safety standpoint (i.e. I don't want the lamp dimming, by itself).

 

I'm now thinking of using one of these flat arrays to act as a primary "face-on" marker, while using a supplemental 921 replacement which fires both radially as well as "face-on" ( http://www.v-leds.com/Shop/Control/Product/fp/vpid/4782916/vpcsid/0/SFV/32481# ), to "fill" the central "clear" reflector area.

 

I will then relocate my current ERD halogen reverse lamp (921 alternative) to another area within the housing.

 

I'm going to allow this to simmer in my head over the weekend, and place orders for components on Monday.

 

Any other ideas/suggestions, brothers and sisters?

OK, time for an update.

 

Winky currently is sporting the factory/unmodified sedan left rear tail-light that brother Petermjc so nicely sold to me for a very fair price. So, I'm rolling around now, looking quite Rice/ghetto.

 

The tail-light disassembly/removal and re-installation on the sedan is exceptionally easy, BTW. Removing the rear cargo hook via its quarter-turn mechanism, and then four bolts and two clips releases the rear tail-light assembly. 10-minute job.

 

For sh1ts and giggles, I first tried to just do a plug-and-play "mockup" of the following 921 (back-up light application) plug-in solution.

 

http://www.v-leds.com/Shop/Control/Product/fp/vpid/4782915/vpcsid/0/SFV/32481

 

This was totally unacceptable in terms of a rear-fog application. Although it did give a good "fill" to the central reverse light reflector area - due to its radial firing pattern - it was definitely not bright enough, either in terms of "fill" nor in terms of dead-on visibility.

 

Based on this experience, I would think that, at the minimum, one of the "3W" or "5W" (3W plus ancillary LEDs) solutions would be mandatory in order to achieve proper end-on brightness [since "fill" brightness is secondary, I won't even bother with that].

 

I've now taken two of the following circuit-board LEDs:

 

http://www.v-leds.com/Shop/Control/Product/fp/vpid/4481142/vpcsid/0/SFV/32481

 

- and configured them in the same 2-row x 6-LEDs (total of 12 LEDs) format as seen in the PIAA DENO3. To achieve this setup, I placed them end-to-end (with the wiring pigtails converging; the separate leads were then soldered together to another length of wiring to afford a single lead, to which I will affix the main switchgear) on a piece of scrap metal that I've cut to-length. The LED boards were then affixed to the metal via 3M Automotive Trim Tape, with a hole drilled at the location of the pigtail leads to clear the wiring.

 

This "LED-plate" was then inserted through the removeable metal plate atop the reverse bulb location, and affixed to the top of the inside of the reverse-light reflector housing, again via 3M Automotive Trim Tape.

 

As I susupect that the metal plate that's there affords a certain amount of heat clearance/shielding, I will use a piece of heat-barrier tape to shield the wiring that I now have trailing through this area.

 

This setup is very bright, end-on, and I am currently satisfied with its performance. At a later date, I may further supplement their radial output (which is currently nil) with a flexible LED array setup.

 

I currently plan to wire into the front fog's circuit, allowing the light to operate in conjunction with the front fogs.

 

Will update.

Thanks for the update. I'm actually still following this thread, and like you, was utterly disappointed by the 921 replacements I ordered.

 

I have a compact flashlight that employs three high-end, high-priced LEDs, with a light output that would absolutely stun you (Elektrolumens "Little Friend", beamshots here: http://www.candlepowerforums.com/vb/showthread.php?t=122623) -- and could serve well in this location, if configured and colored correctly. I'm surprised that no plug-in modules with this brightness exist just yet.

^ Cool!

 

LED flashlights certainly have come a long way since I left the hobby in ~ '04/05.

 

What was then available only as high-end production (i.e. SureFire L6, at a pricetag of over $300) is now nearly commonplace.

 

Honestly, though, I'd have little qualms about putting my Mr.Bulk VIP - with the BigBBH in-place - if I had any clue as to how to make it work in this application.

 

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I haven't been following things ( in-part, this self-exile was chosen to curb my spendings in this area, since Anna's conception and birth )....but is heat-sinking still a problem with the high-powered LED-based flashlights?

 

To this end, the "5W" 1156 solution at Super Bright LEDs (please revisit post #7, on page 1 of this thread) was, as I cited, an interesting item for me, but I couldn't discount the "fine print" on that page, which stated that if the heat-sink was overwhelmed, it will dim....which to me is unacceptable due to the safety/constant-on nature of this particular usage scheme.

 

 

I just want something that's red, really bright (at least to match the output of our brake-lamp) and can run for extended periods....

 

 

No thanks needed, PacCoastFwy. Please, if you've got any ideas, air them!

Shweet, I just bought a second set of tails to experiment with in this respect (I'm just going to mod the drivers side one for the rear fog)...

 

 

And yeah I still have my lightbar and I'm really getting the hankerin to stuff two of the Hellas either behind the grille, or down below sunk back by the radiator

I would love to do this mod; seeing that I don't (like to) fly and I will be making plenty road trips this summer From here to Tampa and back up to Hartford, Chicago and Toronto.

 

subscribe.

^ The recent research articles brought forward by lighting-minded brothers such as outahere really lit a fire under my ass with respect to the rear fog.

 

Since I knew the task should've been easy on the wifey's peanut-eye WRX sedan, I pretty much went out and did it on that car nearly right-away, and I truly felt better about her ( the wifey, not the car ) safety during this past winter's rather awful storms and the single episode of near white-out fog that we saw here in NE-Ohio.

 

And since I'm baby-Anna's primary transport, I also wanted to get this done for Winky, too.

 

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I've now completed wiring from the front fogs into and through the cabin (using the driver's front wheel-well pass-through grommet, and then routing the wire runs along the plastic floor/door edge trim, under the rear bench, and into the trunk). I will finish with the trunk wiring run tomorrow (I ran out of time, due to Anna's nap and dinner, and since she's come down with a cold, I didn't want to risk waking her up by working out there tonight) and will add an in-line fuse on the run as well. Taking the time to well-weatherproof the fog-light power tap, as well as trying to find the lost Pop-It that secures the under-dash panel, really ate up quite a bit of time.....

 

I am contemplating whether or not to install an interrupt switch on the dash. I am not in the habit of running my front fogs under anything other than situations where they may truly be required, hence, this really shouldn't be necessary for me (and it would save me from having another hole in the dash), however, I can see it being advantageous - and besides, it also speaks to the control-freak part of me, too. I think that I'll do without this for the time being, as I've left enough wire-run inside the forward part of the cabin to allow for easy reconfiguration for this need, should I want to do it, later on.

 

Also, now that the major components are in-place, I'm also contemplating additional lighting power as well. Y'all know that I've been very hesitant to chop into the tail-light's "chromed-plastic" reflector array, for fear of collateral damage, but recent encouragement and wisdom from brother VXCL has me thinking that I should be able to effect a cosmetically acceptable (if not exactly show-quality) modification that will allow me to add further lighting elements to "beef-up" output of the rear-fog setup (and relocate the 921 reverse-lamp plug in order to do so).

 

I've had on-order two more rear tail-light wiring harnesses, which were pretty cheap, and that should allow me to experiment some in the coming days. I also plan to order some el-cheapo aftermarket headlight housings from eBay and the like, in order to get in some practice with cutting/shaping the "chromed plastic" sections.

 

Thanks for the encouragement, everyone - and please, keep your ideas and suggestions coming!!!!

I have the rear fogs but not the resistor to power it. So if anybody wants to experiment, I'm selling it for $280 shipped. This is the EDM so it will be on the driver's side.

http://i22.photobucket.com/albums/b346/rbsaeroparts/P2171462.jpg

http://i22.photobucket.com/albums/b346/rbsaeroparts/P2171464.jpg

^ Yummy! That'd be a heck of an experiment/project for someone!

 

Not enough dough, though....

 

 

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Update.

 

Wiring completed.

 

I put in an inline 10-amp at the rear, nestled-up inside the tail-light access port. I haven't worked out the math of this, but I hope it's good enough.

 

I haven't had a chance to go out in the dark to look at things. Baby-Anna has a virus, again ( it seems non-stop this winter, but considering that she's going out to, like, 3 classes and 2 other activities per week, I think it's just par-for-course; or at least the wifey, the Board-licensed pediatrician, seems to think so ), so I didn't want to disturb her sleep.

 

Yes, she sleeps like a Ninja, and yes, she recognizes the sound of my car.

 

From what I can see of it in the daytime, the brightness, dead-on, seems to be at least as bright as my brake-light or hazard/turn signals. This part, I think I'll be happy with when I see it in the dark tomorrow AM.

 

What I am likely not going to be happy with, though, is off-angle viewing. I can see, even now, that the light output decreases drastically as soon as I start to move off-axis.

 

It's likely now, with what's coming up for me in terms of work/play in the next couple of months, that I won't be able to get back to this project for some time. I will likely order some el-cheapo practice light housings to Dremel and mess-around with, as well as continue to search for a "fill/off-axis" solution.