Thanks for the clarification.

To anyone who questions my concerns regarding German electrical engineering, I advise them to take a quick gander at the wiring schematics of the W123 ACC system.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

The alternator light serves as a ballast resistor to "flash" the alternator to make it produce voltage. It has to pass a fair amount of current which is why it takes a 3W bulb. The glowing is a secondary function to its main purpose of being a ballast resistor. Don't bother reinventing the wheel here, stick with the incandescent bulb. It is also there to alert you when the alternator stops charging. It is never fully "switched off", so an LED may continue to glow even if the alternator is charging.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Wiring and electronics are not the Germans' forté. They seem obsessed with bunching things together and mixing in positive and negative switching on a variety of circuits. No schematic is ever drawn the same way twice either.

If you ever want a truly face-palming design, look no further than the seatbelt warning relay on a Gen II W126. Whoever designed that circuit was probably a vegan chef or something and happened to pick up a "DIY" type book on electronics and thought they could handle it. They sure weren't familiar with electric circuitry or common sense.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Just tested my battery with car off and it sits at 12.85v.

Tested the battery cables with engine at idle for 1 minute and its charging at 14.25v. It seems as my alternator is working properly?

If it matters; the LED's have been in the car for 48 hours. I have driven around my small city for about 20-30 minutes twice in that time. And took a 25 mile trip to the park, car sat for 4 hours, and 25miles back. Lights on, radio on, etc.

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Tulare County, CA

WTB list: (1983 300d)
-Exterior rocker panels below doors
-Gauge Custer plastic window/indicator icons

(1983 300D Turbo)

The alternator has the ability to self-flash when the RPM comes up on the engine. In cold/wet weather or when the alternator gets tired (or if you try to jump a dead battery) that alternator light becomes far more important. It's your car, you do what you want. I'd leave the incandescent there to do the purpose it was designed for.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Nor with air-conditioning. A result of building and originally selling cars mostly in a relatively temperate zone where most cars didn't even have AC. Unlike US manufacturers whose customers have to deal with the swamps of LA, the sub-tropics of FL and Death Valley CA.

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'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

Genuinely curious as to what the motivation is here because I still have yet to see a good reason to put LEDs in idiot warning lights mentioned at all. There are numerous benefits to using LEDs in other applications in the car, but none for this use that I can tell - only downsides.

Hoping someone can explain.

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Watch him go!!! link

#dontdealwithkahlil

I agree. I am unable to see any advantage in installing LED lights in the dash. The stock lights are bright enough for me and I am 71 years old with not the best vision. Everyone to their own taste!

Behind the color filter they might even be less bright. All while adding multiple potential failure points per bulb at increased cost compared to an incandescent bulb that typically lasts 40 or 50 years or more.

__________________
Watch him go!!! link

#dontdealwithkahlil

The benefit? It’s a project. My car doesn’t have indicator icons so I wanted to color-code the different bulbs. LEDs also draw less from the the battery.

And every and any type of bulb is a potential failure point. I’ve found several burnt out incandescent bulbs. Incandescent’s also Product more heat. Even the proper wattage bulbs can cause melting when burning out/dying.

You can also change the color of your interior lighting.

Not a project for the faint of heart, but a goal and achievement non the less.

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Tulare County, CA

WTB list: (1983 300d)
-Exterior rocker panels below doors
-Gauge Custer plastic window/indicator icons

(1983 300D Turbo)

Reduced heat and current draw aren't perceivable benefits when the light is only applied for the short time in between key insertion and engine start. Running lights are a different story.

Every bulb is failure point. An incandescent has one: the filament. You've just added about 10 more per bulb with the solder joints and numerous electronic components.

That said, doing it because you want to is a fair reason.

__________________
Watch him go!!! link

#dontdealwithkahlil

I think it's a worthwhile job .

To each their own .

I spend inordinate hours taking things apart, cleaning, lubricating, adjusting and re assembling them just because I enjoy it and I have older high mileage vehicles so I like everything to work "Just So " .

No downside to LED bulbs unless you're afraid of them .

I run LED's in my backup and running lamps and the front turn signals ~ this way I have brighter rear turn signals and the factory transistorized flasher still works .

Once the alternator's drive belts and wiring etc. are fine, the charging voltage depends mainly on the brand of voltage regulator ~ I only use BOSCH and so get 14 VDC when they battery is low and 13 VDC when it's fully changed ~ those off brand regulators rarely reach 13 VDC no matter what .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

In the W201 I've modded the turn signal flasher relay for use with LEDs and run incandescent bulbs in parallel with the brake lamps to maintain function of the cruise control. In another car I had to run an incandescent bulb in parallel with the brake lights to maintain function of the ABS when using LEDs. The instant-on illumination of the brake lights can be considered a safety feature, and in the running lamps it lessens load. In turn signals it's for no real other reason than it looks cute, so by no means am I against using LEDs. But to say there are no downsides is simply untrue. They're failure prone, and it's not usually the diode that will fail it's something else before it.

__________________
Watch him go!!! link

#dontdealwithkahlil

As an old person who's been working on vehicles for over 50 years I can tell you LED's fail just as incandescent bulbs do, what other down side is there ? .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better