LED Bulbs for Taillights/Turn Signals

[Ntrepid]

So I've been thinking about replacing the incandescent bulbs in the taillights of my 93 500E with LED equivalents. From what I have read, it looks like I need to buy LEDs which are colored based on where they are located (i.e. red LEDs for brake, orange for turn signals, etc.). My thought is that using LEDs would be nice as there would be less risk of melting the plastic housing and I would get the near instant on that LEDs provide.

Has anyone done this yet? Any insight on issues to avoid or products you recommend?

Thanks in advance!


Robert

 

[J-Sauce]

The brake lights could be white or red. The housing is tinted so even white lights (like the incandescents we already use) will come out red. Signals may need to be yellow, or red if youd like as thats legal too, depending on which version lights you have. You will have to be careful that the new bulbs are not too wide to fit through the narrow openings into the lenses, and may have to install resistors to keep from getting a "bulb out" indicator, but that is well documented elsewhere online.

 

[gerryvz]

I'd like to see someone do this and post a "HOW-TO" on it.

Why am I always the only one posting HOW-TOs?

 

[Trae]

Quite frankly, we are a little intimidated at your professional way of presenting the jobs to us.
You give beginners, like me, the guts and confidence to do these jobs in the way you lay EVERYTHING out in easy to understand instructions.

Reference my only attempt to do a "how to" on a rear axle:

Rear Axel RR-sm.pdf (328.9 KB, 11 views)

 

[2phast]

I actually use LED tail lights, which are a complete assembly with LED's, ballast etc. Very, very bright, think Cadillac CTS bright! Turn signals and backup lights use regular bulbs though.

In the picture, standard bulbs on the left, LED tail light on the right

 

[clarkz71]

 

[Hollybrook]

Why am I always the only one posting HOW-TOs?

You do such an amazing job with them that perhaps others are intimidated?

 

[M104-AMG]

I actually use LED tail lights, which are a complete assembly with LED's, ballast etc. Very, very bright, think Cadillac CTS bright! Turn signals and backup lights use regular bulbs though.

In the picture, standard bulbs on the left, LED tail light on the right

Can you post a reputable brand and source ?

TIA,
neil

 

[gerryvz]

You do such an amazing job with them that perhaps others are intimidated?

No, I know Dave and others do far more involved/difficult DIY jobs than I would ever dream of doing. Yet nobody documents the work they do. I just wish more folks would is all. Particularly regular maintenance stuff at 15K and 30K service intervals.

 

[2phast]

Can you post a reputable brand and source ?

TIA,
neil

I believe these are the units I purchased.

http://www.ebay.com/itm/1986-1995-M...Parts_Accessories&hash=item2a4760af72&vxp=mtr

 

[Jlaa]

So I've been thinking about replacing the incandescent bulbs in the taillights of my 93 500E with LED equivalents. From what I have read, it looks like I need to buy LEDs which are colored based on where they are located (i.e. red LEDs for brake, orange for turn signals, etc.). My thought is that using LEDs would be nice as there would be less risk of melting the plastic housing and I would get the near instant on that LEDs provide.

Has anyone done this yet? Any insight on issues to avoid or products you recommend?

Thanks in advance!


Robert

I recently found some front turn signals LED bulb replacements (double contact) that:

• Do not trip the bulb out warning indicator
• Do not cause any high frequency flashing

The brand is Lasfit and these bulbs are marketed to specifically be "error free" and "CANBUS compatible". Being very skeptical of these types of claims, especially as these products are always ebay specials, I fired up youtube and watched several aspiring Youtubers install these suckers in their various Yotas/Hondas/Whatever-modernmobile with good results. I must admit that the video production quality of these aspiring youtubers is pretty much universally atrocious.

Here: 2x LED Turn Signal Light Blinker Bulb 1157 2357 Switchback White Amber W Canbus | eBay

Note that I still have incandescent bulbs in my rear turn signals. In the pictures you can see how dim the rear turn signals are compared to the front turn signals (see the reflection on the drywall).

I seem to recall (not with 100% certainty though) that I tried putting in "generic" ebay bulbs in the front signals several years ago .... and I ended up either with high frequency flashing, bulb out warning, or both. I cannot remember exactly which issue it was, but I removed the generic ebay specials because of one or both of those problems.

These "Lasfits" do not exhibit this problem. I will note that when measuring across either of the terminals on the Lasfit LED bulbs, that I show approx 1000 ohms resistance. The generic ebay LEDs show open circuit (of course - its a diode), and the incandescent bulb shows 0.9 ohms or 3 ohms, depending on which terminal you use (see pictures). It appears that the 1000 ohm reading does something to placate either the flasher relay or the BOW.

I took some temperature readings too, see pictures. Anyways, these Lasfit bulbs are very bright when flashing. Almost excessively outrageously bright . It almost hurts to look at it when it is flashing .... but it certainly gets folks' attention.

I will also note that I tried to see what happens with 10 minutes of continuous flashing. After 10 minutes, these Lasfit LEDs seem to enter a "shut down cooling state" (see the marketing literature ---- it trumpets the existence of such a function) whereby the bulbs will flash a bit more rapidly than normal. After a while, the LED bulb cools down and it reverts to normal flashing.

I will see if I can find rear flashing LED bulbs next that also do not trip the BOW or cause high frequency flashing. Lasfit does not seem to make a similarly designed "Error Free" "Canbus compatible" single contact 7506 replacement for the rears flashers though.



(BTW for the rear brake lights, I did the following to put in "generic" LED bulbs in parallel with incandescent bulbs in the fog light sockets in order to fool the BOW circuit). LED bulbs in the rear brake lights and fooling the bulb out warning circuit | Electrical, CAN and Wiring

 

[speedy300dturbo]

Jlaa,

I bought a similar looking set of 1157 switchback "canbus" no-hyper-flash LEDs and although they blinked fine with the headlights / parking lights off, they hyper-flashed once switched on. It's an easy remedy with an additional inline resistor, but haven't got around to it yet.

The rear turn signals seem to be less fussy. I've been running these generic LEDs in the rear blinkers for over a year, with no hyper-flashing: 1156 Ba15s Amber LED Canbus Bulbs No Hyper Flash Car Turn Signal 2x | eBay

 

[Jlaa]

Jlaa,

I bought a similar looking set of 1157 switchback "canbus" no-hyper-flash LEDs and although they blinked fine with the headlights / parking lights off, they hyper-flashed once switched on. It's an easy remedy with an additional inline resistor, but haven't got around to it yet.

Hmmm. The Lasfit bulbs do not exhibit high frequency flashing when the head/parking lights are switched on. Personally I would not use an additional inline load resistor - it feels like a hack to me.

The rear turn signals seem to be less fussy. I've been running these generic LEDs in the rear blinkers for over a year, with no hyper-flashing: 1156 Ba15s Amber LED Canbus Bulbs No Hyper Flash Car Turn Signal 2x | eBay

View attachment 111607

Interesting. I vaguely remember trying to fit generic LEDs in the rear flashers a few yrs ago with suboptimal results. I cannot remember why the results were suboptimal. If you measure resistance between the barrel and the contact of the base of those LEDs you are using, do you get a non-infinite resistance?

The holy grail for me would be to fit an LED in the CHMSL, to reduce the temperature inside the housing and avoid the “melted plastic” phenomenon that afflicts so many w124 CHMSLs. Have you figured out how to do this? I have not.

 

[gerryvz]

Is that a cord to a @gsxr / @JC220 style "desulfator" I see going into your trunk? You're a chip off the ol' block !!!

 

[Jlaa]

Jlaa,

I bought a similar looking set of 1157 switchback "canbus" no-hyper-flash LEDs and although they blinked fine with the headlights / parking lights off, they hyper-flashed once switched on. It's an easy remedy with an additional inline resistor, but haven't got around to it yet.

The rear turn signals seem to be less fussy. I've been running these generic LEDs in the rear blinkers for over a year, with no hyper-flashing: 1156 Ba15s Amber LED Canbus Bulbs No Hyper Flash Car Turn Signal 2x | eBay

View attachment 111607

Thanks. I have discovered, that in conjunction with the absurdly named "Lasfit" LED turn signal bulbs installed in the front in post #11, the installation of equally absurdly named "Katur" LED turn signal bulbs in the rear still yields perfectly normal turn signal operation.

No high-frequency flashing occurs durning turn signal operation, regardless if the headlights are switched on or off. Furthermore, the bulb out warning indicator is not tripped.

https://www.amazon.com/gp/product/B082HK33HQ/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&th=1

As well, these "Katur" bulbs are also extremely bright. I will note though that resistance across these bulbs measured around 6-10 megaohms --- pretty much infinite resistance, unlike the "Lasfit" bulbs in post 11 which measured 1000 ohms.

I have some pictures below. I measured around 153F after a couple minutes of flashing.

 

[Jlaa]

I have fitted Red "Katur" "Error Free Canbus compatible" LED bulbs in the brake lights of my 500E. This includes the CHMSL. The Bulb Out Warning light is not tripped.

EDIT - 2020-9-5 - I regret to inform everyone that the Katur LED operates fine for the first 2 minutes of continuous usage in the CHMSL (brake applied for 2 minutes). After 2 minutes, the heat buildup in the LED bulb changes something about the response curve of the circuitry inside the bulb, and the bulb out warning light is tripped. :-(

After two minutes, if you reset the BOW light (restart the car) and immediately reapply the brake, the BOW returns, since the LED bulb is still hot. However, if you reset the BOW light and let the LED cool by not applying the brake for a while, you get a variable amount of time, ranging from a few seconds to 2 minutes, of continuous brake operation, until the BOW light trips again.

I consider this to be some kind of design incompatibility with the CHMSL (as opposed to manufacturing defect). After reverting the CHMSL to an incandescent bulb, I have verified that the BOW light does not occur with an incandescent bulb.

Therefore my conclusion is --- Katur LED bulbs work fine for the left/right brake lights without any BOW lights being tripped, but the CHMSL still requires an incandescent bulb. Oh well. Incremental progress.

I will be keeping the set of Katur LED bulbs that I put in the brake lights, and I will return the one in my CHSML.

My motivation for doing this was to try and reduce the temperature in the CHMSL, which is known to melt. I have already rectified the beginning of melty-glossiness on one of the black bars of my CHSML by repainting the black bar w/ matte black paint. Note that I bought these bulbs on Amazon because Amazon facilitates free and easy returns in the event that the bulbs didn't work.

https://www.amazon.com/gp/product/B082HJWS4H/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

I powered each bulb - the conventional incandescent 7506 and the Katur LED bulb - for several minutes and attempted to measure the temperature. I'm fairly confident I got the temp on the LED bulb right, but I'm not confident I measured temps on the incandescent bulb right, as the temperature read seemed super highly sensitive to shifting the temp gun 1 or 2mm off "axis".

Temps for the Katur and the 7506 from head-on were 192F and 338F respectively.
Temps for the Katur and the 7506 with the gun held 45* pointing @ the side of the buln were 218F and 310F respectively.



With the 7506 fitted into the CHMSL, I measured 9mm as the closest distance from the bulb to melty-plastic. With the Katur, it was 13mm (12.99).



Here is the Katur in the CHMSL

 

[JAB12]

I like the way the reflection hits the 993 in front of the .036. Great post, thank you for the details.

 

[Jlaa]

Here is a comparison. LED on the left, Incandescent on the Right, and LED in the CHMSL. As described above, no bulb-out-warning lights. Finally the holy grail (had to wait a couple years for this to exist)

EDIT - 2020-9-5 - I regret to inform everyone that the Katur LED operates fine for the first 2 minutes of continuous usage in the CHMSL (brake applied for 2 minutes). After 2 minutes, the heat buildup in the LED bulb changes something about the response curve of the circuitry inside the bulb, and the bulb out warning light is tripped. :-(

After two minutes, if you reset the BOW light (restart the car) and immediately reapply the brake, the BOW returns, since the LED bulb is still hot. However, if you reset the BOW light and let the LED cool by not applying the brake for a while, you get a variable amount of time, ranging from a few seconds to 2 minutes, of continuous brake operation, until the BOW light trips again.

I consider this to be some kind of design incompatibility with the CHMSL (as opposed to manufacturing def ect). After reverting the CHMSL to an incandescent bulb, I have verified that the BOW light does not occur with an incandescent bulb.

Therefore my conclusion is --- Katur LED bulbs work fine for the left/right brake lights without any BOW lights being tripped, but the CHMSL still requires an incandescent bulb. Oh well. Incremental progress.

I will be keeping the set of Katur LED bulbs that I put in the brake lights, and I will return the one in my CHSML.

 

[gsxr]

Any word if drivers behind you are blinded?

Sooo.... how about the single fog lamp?

 

[Jlaa]

Any word if drivers behind you are blinded?

Sooo.... how about the single fog lamp?

Probably yes, and ask and you shall receive. :;-)

 

[gerryvz]

For posterity and benefit of the membership, please post the manufacturer, part number, and links to availability.

 

[Jlaa]

For posterity and benefit of the membership, please post the manufacturer, part number, and links to availability.

Sure. For the brake lights, I referenced these in post 16, but the price seems to have gone up from 19.99 to 22.99 / pair since I posted them in post 16. Furthermore, the red ones seem to have lost their prime status, meaning shipping costs extra. Surely shipping costs are something that are alien to those with charmed lives, and I empathize with the horror of suddenly having to pay for shipping.

https://www.amazon.com/gp/product/B082HJWS4H/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&th=1&psc=1

You can probably get these cheaper on ebay, but the benefit of buying from Amazon is the insurance of having painless returns in the event of a malfunction.

 

[Jlaa]

I regret to inform everyone that the Katur LED operates fine for the first 2 minutes of continuous usage in the CHMSL (brake applied for 2 minutes). After 2 minutes, the heat buildup in the LED bulb changes something about the response curve of the circuitry inside the bulb, and the bulb out warning light is tripped. :-(

After two minutes, if you reset the BOW light (restart the car) and immediately reapply the brake, the BOW returns, since the LED bulb is still hot. However, if you reset the BOW light and let the LED cool by not applying the brake for a while, you get a variable amount of time, ranging from a few seconds to 2 minutes, of continuous brake operation, until the BOW light trips again.

I consider this to be some kind of design incompatibility with the CHMSL (as opposed to manufacturing def ect). After reverting the CHMSL to an incandescent bulb, I have verified that the BOW light does not occur with an incandescent bulb.

Therefore my conclusion is --- Katur LED bulbs work fine for the left/right brake lights without any BOW lights being tripped, but the CHMSL still requires an incandescent bulb. Oh well. Incremental progress.

I will be keeping the set of Katur LED bulbs that I put in the brake lights, and I will return the one in my CHSML.

 

[gerryvz]

 

[Jlaa]

OK I would like to try a different approach to getting a low-temperature LED bulb inside the 3rd brake light (CHMSL), especially to reduce the temperature inside the melt-prone housing. I watched this Australian gentleman on youtube:

and after reading through his comments, I realized that non US-market cars DO NOT monitor the CHMSL via the N7 bulb out warning relay.

Indeed, looking through the EPC:

- US Market N7 BOW relay = 126.542.01.32
- Japan / Europe Market N7 BOW relay = 126.542.03.32

These are used across all variants of w124s.



Furthermore, looking through the Electrical Troubleshooting Manual (I guess I have @gsxr's archived copy which is used for US market cars) I can see that US Market N7 BOW Relays use pin 54a to monitor the CHMSL:


My question is two-fold -

Does any of our non-US market members have a couple of 126.542.03.32 sitting in their hoards that they could sell me? Ideally I would like to buy two just in case one is non-functional? @JC220, any of these buggers in your parts-majal? I would be very grateful.

Secondly, does anyone have this page of the electrical troubleshooting manual for NON-US-Market cars, such that I could compare if the rest of the pins for N7 match up to the same bulbs on a US car?

Many Thanks,
jlaa

 

[Jlaa]

I am pleased to report that using a Euro N7 relay 126.542.03.32 and modifying it slightly with some light soldering and cutting works well! I have some road time on this both day and night, so I know it works in the real world, with traffic, using cruise control (which is tied into the brake circuit, etc.) Now I have fast acting LEDs in all five brake bulb positions of my 500E. The light output is absurdly bright, and this now maximizes the chance that inattentive drivers will see me braking and reduce the likelihood that they will rear-end my car.

At the same time, I still have a functioning BOW system in the car - no missing dash bulbs here. And, the best part is that I can use a non-CANBUS LED in the CHMSL ... low heat (approx 100F after 3 min continuous operation) and I never have to be concerned about the super-common-dreaded lens-melt seen on so many w124s/201s/126s.

I'd like to see someone do this and post a "HOW-TO" on it.
Why am I always the only one posting HOW-TOs?

The procedure to modify the Euro N7 relay is here: HOW-TO: Prevent 3rd brake light (CHMSL) from melting by using low-heat LEDs WITHOUT Tripping the Bulb out Warning Light | "HOW-TO" Tutorial Articles

I now have srockpiled one primary Euro N7 and one backup Euro N7 as a spare for the future.

 

[Provet]

I am pleased to report that using a Euro N7 relay 126.542.03.32 and modifying it slightly with some light soldering and cutting works well! I have some road time on this both day and night, so I know it works in the real world, with traffic, using cruise control (which is tied into the brake circuit, etc.) Now I have fast acting LEDs in all five brake bulb positions of my 500E. The light output is absurdly bright, and this now maximizes the chance that inattentive drivers will see me braking and reduce the likelihood that they will rear-end my car.

At the same time, I still have a functioning BOW system in the car - no missing dash bulbs here. And, the best part is that I can use a non-CANBUS LED in the CHMSL ... low heat (approx 100F after 3 min continuous operation) and I never have to be concerned about the super-common-dreaded lens-melt seen on so many w124s/201s/126s.




The procedure to modify the Euro N7 relay is here: HOW-TO: Prevent 3rd brake light (CHMSL) from melting by using low-heat LEDs WITHOUT Tripping the Bulb out Warning Light | "HOW-TO" Tutorial Articles

I now have srockpiled one primary Euro N7 and one backup Euro N7 as a spare for the future.
View attachment 113837