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What is this warning light?

Started by 1980sdga, 04 April 2011, 09:36 PM

1980sdga

The circle with the 3 "slashes" on either side flashes yellow every so often.  It looks like it should be a brake light but there is a red one that says "BRAKES". 

What is it?  It sort of looks like Darth Vaders Tie-Fighter but I didn't see him behind me or anything...

Squiggle Dog

Q. "What is this warning light?"

A. Famous last words!

Just joking. I believe that is the brake wear sensor which tells you that your brake pads are down to the metal and need to be replaced. The one that says "BRAKE" tells you that your parking brake is on.
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1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

1980sdga

Thanks!

I just put new pads on the front and it looked good when it went back together. I guess those little wires that go inside the pads trigger this light?  I'm thinking that I may have metallic pads that sometimes complete the circuit or maybe it's just tempermental like the rest of the car  ;D

Pretty neat way of running a warning light!

Squiggle Dog

Yeah, those wires trigger the light. The insulation tends to crack and that could cause them to short circuit, or there may be a bad ground connection behind the gauge cluster that is arcing over to the brake pad wear warning light. It's a good system to have so you don't chew up your rotors.
Stop paying for animal cruelty and slaughter. Go vegan! [url="https://challenge22.com/"]https://challenge22.com/[/url]

1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Heated Seats, 350,000+

koan

Did you use new sensors ?

If not and the insulation of the sensor (it's just a bit of metal covered in plastic) has worn away the light can glow because of the conductivity of sintered metal pads.

On mine the pad warning and brake fluid level warning lights are next to each other and since they just push in to holes in the back of the cluster it's possible to swap them over accidentally.

koan
Boogity, Boogity, Boogity, Amen!

Big_Richard

other cars use a bit of metal to rub on the disk when the pad material is around 2mm thick or less.

The constant squeal ensures that the car gets inspected before disaster by anyone other than the most negligent (female) drivers.

The brake pad wear detection system is a bit more in your face and less likely to be ignored in my opinion ;)

I guess it helps when the warning is clear and easily understood - ie, not like on the w116..