From MBUSA site:
"9. IMPORTANT: Check that the brake light bulb in each tail light unit of your car is an original equipment OSRAM or BOSCH bulb. Do not use U.S. type 1157 bulbs--they can damage the control unit beyond repair!"
I have heard this as a rumor, and as reality. is this true?
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

First guess would be that only applies to models with the "bulb out" warning module, like the W124.

I wonder why that is though? What's the connection between the two?

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon

The cruise control gets a ground signal through the brake lamp bulbs. This ground condition goes to "neutral" when you step on the brake. That is what causes the cruise control to drop out when you tap the brakes. There might be some way that the cc could be damaged, but the usual result of incorrect bulbs or burned out bulbs is that the cc won't work correctly.

i thought it was crappy solder???

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

There will not be any damage. The CC amp is lust looking for a ground path.

They just want you to buy more of their stuff.

The terminal goes High (+12 Volts) -- not 'neutral' -- when you step on the brake and the brake switch activates to turn on the brake light. You're right as to the effect. If both (all?) of the brake lamps are missing or burned out, the ground condition can never appear and the CC always thinks the brakes are on, hence won't engage.

While we're here, what about LEDs? Will an aftermarket LED brakelight module provide the ground path that the CC needs? Anyone ever try one?

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"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

As I mention in this post, LEDs will have the same unwanted effect on the cruise control.

The reason MBUSA uses the word is that the 1157 is a dual filament bulb, not a single filament, like ours (or an 1156). The use of a specific brand is not required according to the experts at GDL, the gurus of cruise control , but it does need to be the right type of bulb.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)