I'm waiting for my soldering iron to heat up so I figured I'd give it ago:

From what the scope says, it looks like the PWM controller outputs about 160 Hz signal. Here's the datasheet on the IC: http://www.datasheetcatalog.org/datasheet/stmicroelectronics/1408.pdf



I had some random 2V, 20mA Red LED sitting around, I threw a 500 Ohm resistor on it and here's the result. It does indeed dim... With better/brighter LED's you could probably achieve a better result.

For wiring reference:


Video, I didnt see any strobing effect when I filmed this:

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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

those pots are $2 ea at my local pick a part.

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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."

If you have a bad air flow potentiometer and one can be replaced with a new one why care if it is china that manufactured it? it might not last as long as the original but what after market item dose? ALL I am asking is there enough interest in it to make it worth my time to offer them! at a good price.

Just-In-Time, I appreciate your thoughtful offer. Those potentiometers are hard to find.

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2012 E350
2006 Callaway SC560

yes and I was turned on to this by another member and thought I would make contact with the intention of stocking some, I just thought I would run this by every who keeps the older equipment, but I do not wish to have a hundred units sitting in limbo.

Bought mine from him, for a spare.
Air flow potentiometer Mercedes 190E 16V 300E 560SEL | eBay

SG-Motorsports Air Flow Meter Potentiometer Replacement

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85' 190E w/collector plates

If this is for W123 300D 1984 model, I am interested. How much will it cost? Is this brand new or reworked?

On the LED being run from a PWM source.

If strobing is an issue, a capacitor could be added in parallel to the output to smooth things out. Depending on how large the cap is and max current availible from the PWM unit, a resistor might need to be added in series to the cap to limit charging inrush current when things are turned on.

( The resistor might be needed because a capacitor looks like a dead short until it charges up. )