I'm looking at replacing the turn signal lights in my '83 300D with LED bulbs, but I'm wondering how to handle the whole hyper-flashing issue. I've been trying to find an electronic flasher unit for the car and had no luck at all, does anyone know of a source? Or is there even such a thing for a W123? In the end I could always settle for load resistors or maybe try CAN Bus bulbs, but I'd far, far rather replace the flasher if possible.

If anyone can help, I appreciate it in advance.

Total current used is inconsequential in this application. Load resistors would be the simple approach.

It's been awhile since I played with the electrical system in a 123. If it uses a relay and timer circuit to blink the lights then the load doesn't matter. If it's a load-based system then you'd have to add load resistors or adapt a later relay, for example, one from a 124.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I put LED turn signals in my truck and if the flasher unit in your Benz is a standard unit, you may be able to buy a LED compatible flasher from Advance Auto parts like I did.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

IIRC late W123s use a standard type relay mounted near the gearshift.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I believe there are led bulbs that have the resistors built in. It's called a CAN BUS led bulb. Used on newer car circuits that have sensors for burnt out lights. They may work for turn signals also. Superbrightled is where I saw them.
There is an Auto specific bulb finder on the site.

You dont need a new flasher. I replaced my turn signal dash lights with LED's using the old bulb holder.

Unsolder the old bulb leaving the existing resistor in place. Solder in the LED bulb.
Reinstall into the dash but check that its working before you remount the instrument cluster to insure you have the right polarity. If the bulb doesnt like, just rotate it 180 degrees.

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

No freakin' clue, electrical issues are not my forte. Should be easy to check by pulling the brake light LEDs and trying them in the turn signal sockets and seeing what happens, I suppose.

The flasher units I've seen for sale for my w123 seem to have a sort of square pattern with round connectors, and they don't appear to be common at all from what I saw during my first round of Google-ing. I was hoping to have a electronic flasher in hand before taking apart the console, but I guess I'll just have to stop being lazy and go ahead and tear it down and confirm what I have.

So I'll try switching the brake LEDs and see if I have a problem in the first place. If so, I'll pull the old flasher relay to confirm I can't just get an off-the-shelf electronic replacement. If not, and no one can refer me to an electronic w123-compatible relay, I'll probably try a set of CAN bus LED bulbs before going to wired-in load resistors.

I have elsewhere read theorizing that the resistors built into CAN bus bulbs lead to heat build up and shorten the lives of the LEDs, and this is why Superbrightleds doesn't want you to put CAN bus bulbs in a non-CAN bus vehicle. I don't put a lot of stock in that worry because it would be, what, like ten watts worth of heat? Even on a bulb running for hours at a time like the front running/turning lights wouldn't get killed like that, it's nothing compared to being in the hot sun all day. Besides, the heat build up would be the same in a CAN-bus car, wouldn't it? But if any more electrically-inclined person out there knows why I shouldn't run a CAN bus bulb, I'd be glad to hear it.

Thanks, everyone, for your input!

If you can locate a flasher that operates on an electric/electronic time constant circuit it does not matter what bulbs are used. Try the flasher manufactures on the web.

Flashers with simple bimetallic strips have to see enough current flow to set the intended frequency of flashing. Reduce the current with one bulb out and you get a much different flashing rate most have noticed I think.

I have never had a reason to take the earlier flasher apart. I suspect it restores the closed contact position faster as it did no get as hot when opening up. This reduces the return to closed contact time.

For a flasher system load a couple of bulbs wired into each side would also keep the old rate of flashing with leds as well. You could put them anywhere and painting them black should not hurt. Or even in a closed small box. Just do not wire the running lights into those contained bulbs as well.