GMC 1993 Suburban Owner's Manual page 185

K2325
This light appears on your instrument cluster to warn you i f your regular
braking system needs sewice. See "Brake System Warning Light" in the
Index.
Disc Brake Wear Indicators
Disc brake pads have built-in wear indicators that make a high-pitched
warning sound when the brake pads are worn and new pads are needed.
The sound may come and
go or be heard all the time your vehicle is moving
(except when you are pushing on the brake pedal firmly).
The brake wear warning sound means that sooner or later your your
brakes won't work well, That could lead to an accident. When you
hear the brake wear warning sound, have your vehicle serviced.
Continuing
to
drive with worn-out brake
pads
couki
result in
costly
brake
mpair.
I
Some driving conditions or climates may cause a brake squeal when the
brakes are first applied or lightly applied. This does not mean something
is
wrong with your brakes.
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