Author Topic: low brake fluid warning light -- late 250 SL  (Read 112 times)

zak

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low brake fluid warning light -- late 250 SL
« on: October 02, 2025, 22:35:45 »
The float in my brake fluid reservoir has disintegrated so the dash low brake fluid warning light is coming on .
My brake fluid reservoir is full.

I read in the  Tech Manual that that dash light also signals if a door is ajar. The warning light has never ever gone on when the car is running and a door is opened so it is either non operative or not a feature of a European model.

Was the door ajar warning light restricted to only US market cars or only 280 SL models as a later US safety feature ?
My car is a french market, late model 250 SL. I am wondering if my car has the door ajar feature or not.
I will be ordering aboth a new float ( and a new brake fluid reservoir for aesthetics ), but I am concerned how the fuel pump is activated when the door is ajar.

thanks,

jz   
1967 250 SL
1983 280 SL
2015 ML 250 Bluetec
2007 ML CDI
2004 E 320 Wagon
1999 E300 Turbodiesel

BHap

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Re: low brake fluid warning light -- late 250 SL
« Reply #1 on: Today at 05:33:11 »
On my 280SL, the master cylinder failed over the winter one year and caused the low fluid light to come on. By coincidence, I tried to turn the engine off with the driver door open, and to my surprise, the car kept running. Not sure if the 250 is similar, but apparently the brake fluid level and door ajar light share a circuit with the ignition. When the door is open, the dash light illuminates and if the fluid level light is on, 12v backfeeds to the ignition. If you search the forum, there is a fix that involves installing a diode to prevent 12v from backfeeding.
Bob Happe
Pittsburgh, Pa
1970 280SL, white/black 4 speed

AndrewB

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Re: low brake fluid warning light -- late 250 SL
« Reply #2 on: Today at 08:34:31 »
On my 2 UK spec Pagodas, the red light goes on when the door is opened
1969 280SL (unrestored)
1970 280SL (fully restored)
1971 Range Rover Suffix A Kingsley Restomod
1987 500SL
2002 Porsche 996 Targa
2011 Landrover Defender TdCi
2019 Mercedes S560 Cabriolet

 

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